The ultrafine copper wire with a diameter of 18μm is prepared via cold drawing process from the single crystal downcast billet(Φ8 mm),taking a drawing strain to 12.19.In this paper,in-depth investigation of the micr...The ultrafine copper wire with a diameter of 18μm is prepared via cold drawing process from the single crystal downcast billet(Φ8 mm),taking a drawing strain to 12.19.In this paper,in-depth investigation of the microstructure feature,texture evolution,mechanical properties,and electrical conductivity of ultrafine wires ranging fromΦ361μm toΦ18μm is performed.Specially,the microstructure feature and texture type covering the whole longitudinal section of ultrafine wires are elaborately characterized.The results show that the average lamella thickness decreases from 1.63μm to 102 nm during the drawing process.Whereas,inhomogeneous texture evolution across different wire sections was observed.The main texture types of copper wires are comprised of<111>,<001>and<112>orientations.Specifically,the peripheral region is primarily dominated by<111>and<112>,while the central region is dominated by<001>and<111>.As the drawing strain increases,the volume fraction of hard orientation<111>with low Schmid factor increases,where notably higher fraction of<111>is resulted from the consumption of<112>and<001>for the wire ofΦ18μm.For drawn copper wire of 18μm,superior properties are obtained with a tensile strength of 729.8 MPa and an electrical conductivity of 86.9%IACS.Furthermore,it is found that grain strengthening,dislocation strengthening,and texture strengthening are three primary strengthening mechanisms of drawn copper wire,while the dislocation density is the main factor on the reducing of conductivity.展开更多
Owing to the lack of matching commercial welding wires,the development of wire arc additive manufacturing(WAAM)for most aluminum alloys is hindered.A wire-powder synchronous arc additive manufacturing(WPAAM)was propos...Owing to the lack of matching commercial welding wires,the development of wire arc additive manufacturing(WAAM)for most aluminum alloys is hindered.A wire-powder synchronous arc additive manufacturing(WPAAM)was proposed to prepare the target Al-Si-Mg aluminum alloy.Based on the synchronous deposition of AlSi_(12) wire and pure Mg powder,the deposition width of the WPAAMed thin-wall was increased by 61% compared with that of WAAMed thin-wall using AlSi_(12) wire,and the machining allowance was reduced by 81%.The added Mg powder benefited to form refined equiaxed grains,and reduced the average grain size of the WPAAMed thin-wall to 47.1μm,showing a decrease of 23.8% relatively to that of the WAAMed thin-wall.Besides,Mg reacted with Si to form Mg_(2)Si strengthening phases.The mechanical properties tests showed that the ultimate tensile strength and elongation of the WPAAMed thin-wall increased up to 174.5 MPa and 4.1%,reaching 92% and 60% those of the WAAMed thin-wall,respectively.展开更多
BACKGROUND Correcting skeletal class III malocclusion with anterior crossbite in adolescents using only orthodontic treatment poses challenges.This report highlights a novel approach leveraging improved superelastic N...BACKGROUND Correcting skeletal class III malocclusion with anterior crossbite in adolescents using only orthodontic treatment poses challenges.This report highlights a novel approach leveraging improved superelastic Ni-Ti alloy wire(ISW)to address these conditions effectively.CASE SUMMARY A 17-year-old male patient presented with the chief complaint of an underbite.The patient was given a diagnosis of skeletal class III malocclusion and anterior crossbite.The orthodontic treatment plan was implemented and did not require teeth extractions or orthognathic surgery.Key interventions involved the app-lication of ISW,intermaxillary elastics,and ISW unilateral multi-bend edgewise archwire.The unique combination of these techniques enabled the correction without the need for extractions or surgery.This approach leverages the advanced biomechanical properties of ISW,including its super-elasticity and shape memory,to enhance treatment efficacy.The treatment lasted 17 months,and major improvements in overjet,overbite,and alignment were achieved.The results were favorable,and stability was discovered during follow-up.CONCLUSION The application of ISW for treating skeletal class III malocclusion with anterior crossbite in a 17-year-old male patient resulted in exceptional outcomes.The treatment led to a marked improvement in the patient’s facial profile and to proper overjet,overbite,and midline alignment.These results were maintained over a one-year follow-up,indicating that a minimally invasive orthodontic approach can effectively address complex skeletal discrepancies in adolescent patients.This case illustrates that with the careful use of advanced orthodontic techniques,major skeletal challenges can be resolved without resorting to surgical procedures.展开更多
The low accuracy of wire arc additive manufacturing(WAAM)is one of the main factors limiting its development,and is detrimental to the mechanical properties of WAAM structures.This study primarily investigated the eff...The low accuracy of wire arc additive manufacturing(WAAM)is one of the main factors limiting its development,and is detrimental to the mechanical properties of WAAM structures.This study primarily investigated the effects of wire-feeding directions and positions of the molten pool on the quality and accuracy of unsupported WAAM.First,the three-dimensional(3D)morphology and volume of unsupported rods manufactured with different wirefeeding directions were quantitatively evaluated using a 3D scanning method.The effects of the wire-feeding direction and arc length on the volume and standard deviation of the unsupported rods are then discussed in detail.Finally,the influence of the wire-feeding direction on the quality and accuracy of unsupported WAAM is discussed and revealed by combining the temperature gradients,surface tension,and contact angles.The research revealed that feeding a wire into the high-temperature zone of the molten pool could reduce material spatter and achieve higher precision.The volume of the sample fed into the high-temperature zone was 120%of that fed into the low-temperature zone.This reduced not only the material waste but also the standard deviation of the diameter of the same group of samples.This research is of great significance and value for high-quality unsupported WAAM.展开更多
Based on comprehensive observations of 20 wire icing events during winter from 2019 to 2021,we investigated the characteristics of the icing properties,the atmospheric boundary layer structure,the raindrop size distri...Based on comprehensive observations of 20 wire icing events during winter from 2019 to 2021,we investigated the characteristics of the icing properties,the atmospheric boundary layer structure,the raindrop size distribution,and their associated effects on the ice accretion mechanism in the mountainous region of Southwest China.The maximum ice weight was positively correlated with the duration of ice accretion in the mountainous area.The duration of precipitation accounted for less than 20%of the icing period in the mountainous area,with solid-phase hydrometeors being predominant.Icing events,dominated by freezing rain(FR)and mixed rain–graupel(more than 70%),were characterized by glaze or highdensity mixed icing.The relationship between the melting energy and refreezing energy reflected the distribution characteristics of the proportion of FR under mixed-phase precipitation.The intensity of the warm layer and the dominant precipitation phase significantly affected the variations in the microphysical properties of FR.The melting of large dry snowflakes significantly contributed to FR in the mountainous areas,resulting in smaller generalized intercepts and larger mass-weighted mean diameters in the presence of a stronger warm layer.Under a weaker warm layer,the value of the massweighted mean diameter was significantly smaller because of the inability of large solid particles to melt.Finally,FR in the mountainous area dominated the ice weight during the rapid ice accumulation period.A numerical simulation of FR icing on wires effectively revealed the evolution of disaster-causing icing in mountainous areas.展开更多
The feasibility of manufacturing Ti-6Al-4V samples through a combination of laser-aided additive manufacturing with powder(LAAM_(p))and wire(LAAM_(w))was explored.A process study was first conducted to successfully ci...The feasibility of manufacturing Ti-6Al-4V samples through a combination of laser-aided additive manufacturing with powder(LAAM_(p))and wire(LAAM_(w))was explored.A process study was first conducted to successfully circumvent defects in Ti-6Al-4V deposits for LAAM_(p) and LAAM_(w),respectively.With the optimized process parameters,robust interfaces were achieved between powder/wire deposits and the forged substrate,as well as between powder and wire deposits.Microstructure characterization results revealed the epitaxial prior β grains in the deposited Ti-6Al-4V,wherein the powder deposit was dominated by a finerα′microstructure and the wire deposit was characterized by lamellar α phases.The mechanisms of microstructure formation and correlation with mechanical behavior were analyzed and discussed.The mechanical properties of the interfacial samples can meet the requirements of the relevant Aerospace Material Specifications(AMS 6932)even without post heat treatment.No fracture occurred within the interfacial area,further suggesting the robust interface.The findings of this study highlighted the feasibility of combining LAAM_(p) and LAAM_(w) in the direct manufacturing of Ti-6Al-4V parts in accordance with the required dimensional resolution and deposition rate,together with sound strength and ductility balance in the as-built condition.展开更多
The Kirschner wire(K-wire)is widely used in orthopedic external fixation due to its versatility and clinical effectiveness.However,a significant challenge associated with its use is the potential for bacterial migrati...The Kirschner wire(K-wire)is widely used in orthopedic external fixation due to its versatility and clinical effectiveness.However,a significant challenge associated with its use is the potential for bacterial migration,subsequent infection,and dislodgement as the wire penetrates the skin and bone.This study introduces a novel bioactive material,selenium/calcium silicate(Se/β-CS),achieved by integrating selenium-an essential trace element in the human body-into bioceramic calcium silicate.This integration was accomplished using a combined chemical co-deposition method and redox reaction.Furthermore,a uniform and controllable Se/β-CS coating was applied to the K-wire's surface using the Langmuir-Blodgett technique.This coating gradually releases active components-Si,Ca,and Se-that effectively eliminate bacterial infections and promote osteointegration.The findings of this study offer promising opportunities for the use of robust and multifunctional coating materials on implantable devices,particularly within the fields of orthopedics,transplantation,and surgery.展开更多
Simultaneously improving the strength and electrical conductivity of conducting metallic materials is of great significance,but it still remains a key challenge as the two properties are often mutually exclusive.In th...Simultaneously improving the strength and electrical conductivity of conducting metallic materials is of great significance,but it still remains a key challenge as the two properties are often mutually exclusive.In this study,we demonstrate a“<111>oriented fibrous grains with ultra-high aspect ratio”strategy for breaking such a conflict in Cu wire,which relies on the distinctive spatial distribution of grain boundaries and the highly consistent hard orientation to play their respective roles in suffering loading and conducting,thereby enabling a separate optimization of both strength and electrical conductivity.Therefore,a processing route was designed,involving directional solidification followed by large drawing deformation,to successfully construct fibrous grains with an ultra-high aspect ratio in 596.7 and ultra-high<111>texture proportion over 97%,which achieves Cu wire with a remarkable combination of yield strength in 482.3 MPa and electrical conductivity in 101.63%IACS.Finally,the mechanisms for high strength and high electrical conductivity were quantitatively discussed.展开更多
To investigate the performance of utilizing the shape memory effect of SMA(Shape Memory Alloy)wire to generate recovery stress,this paper performed single heating recovery stress tests and reciprocating heating-coolin...To investigate the performance of utilizing the shape memory effect of SMA(Shape Memory Alloy)wire to generate recovery stress,this paper performed single heating recovery stress tests and reciprocating heating-cooling recovery stress tests on SMA wire under varying initial strain conditions.The effects of various strains and different energized heating methods on the recovery stress of SMA wires were explored in the single heating tests.The SMA wire was strained from 2%to 8%initially,and two distinct heating approaches were employed:one using a large current interval for rapid heating and one using a small current interval for slower heating.The experimental outcomes reveal that during a single heating cycle,the temperature-recovery stress relationship of SMA wire exhibits three distinct stages:the martensite phase stage,the transition stage from martensite to austenite phase,and the austenite phase stage.Notably,the choice of heating method does not influence the maximum recovery stress value,and the correlation between initial strain and maximum recovery stress is predominantly linear.Moreover,conducting the reciprocating temperature rise and fall performance test is important to better simulate the scenario in practical engineering where multiple recovery stress in SMA wires for structural repair.In this test,two temperature cycling methods were studied:interval rise and fall,as well as direct rise and fall.In the case of utilizing the interval temperature rise and fall method,it was observed that the recovery stress associated with cooling was significantly higher than that corresponding to heating at the same temperature.Furthermore,the recovery stress was lower upon subsequent heating than that measured during the previous heating cycle.Based on the experimental results,a prediction model for the temperature-recovery stress relationship has been proposed to simplify numerical calculations.It is hoped that an approximate temperaturerecovery stress curve can be obtained from the parameters of the SMA wire.The calculated values derived from this model show good alignment with the measured values,indicating its reliability.展开更多
The performance and price of copper-based micro linear products are determined by the diameter uniformity.How to accurately detect the wire diameter of long-length copper based micro linear products without cutting or...The performance and price of copper-based micro linear products are determined by the diameter uniformity.How to accurately detect the wire diameter of long-length copper based micro linear products without cutting or damage has always been a technical concern for production enterprises.Herein,a novel approach was developed for nondestructive detection of the average diameter at any given segment of a long copper wire by assessing the adsorption capacity of arginine on its surface.The amount of adsorbent on the surface of the copper wire exhibits a positive correlation with the area,which can be detected by extractive electrospray ionization mass spectrometry(EESI-MS)after online elution with ammonia.The experimental results demonstrated that the analysis can be completed within 15 min,with a good linear relationship between copper wires with different diameters and the adsorption capacity of arginine.The linear correlation coefficient R2was 0.995,the relative standard deviation was 1.10%-2.81%,and the detection limit reached 2.5μm(length of segment=4 cm),showing potential applications for facile measurement of the average diameter of various metal wires.展开更多
Buckling failure in submarine cables presents a prevalent challenge in ocean engineering.This work aims to explore the buckling behavior of umbilical cables with damaged sheaths subjected to compression and bending cy...Buckling failure in submarine cables presents a prevalent challenge in ocean engineering.This work aims to explore the buckling behavior of umbilical cables with damaged sheaths subjected to compression and bending cyclic loads.A finite element model is devised,incorporating a singular armor wire,a rigid core,and a damaged sheath.To scrutinize the buckling progression and corresponding deformation,axial compression and bending cyclic loads are introduced.The observations reveal that a reduction in axial compression results in a larger number of cycles before buckling ensues and progressively shifts the buckling position toward the extrados and fixed end.Decreasing the bending radius precipitates a reduction in the buckling cycle number and minimizes the deformation in the armor wire.Furthermore,an empirical model is presented to predict the occurrence of birdcage buckling,providing a means to anticipate buckling events and to estimate the requisite number of cycles leading to buckling.展开更多
Ice cover on transmission lines is a significant issue that affects the safe operation of the power system.Accurate calculation of the thickness of wire icing can effectively prevent economic losses caused by ice disa...Ice cover on transmission lines is a significant issue that affects the safe operation of the power system.Accurate calculation of the thickness of wire icing can effectively prevent economic losses caused by ice disasters and reduce the impact of power outages on residents.However,under extreme weather conditions,strong instantaneous wind can cause tension sensors to fail,resulting in significant errors in the calculation of icing thickness in traditional mechanics-based models.In this paper,we propose a dynamic prediction model of wire icing thickness that can adapt to extreme weather environments.The model expands scarce raw data by the Wasserstein Generative Adversarial Network with Gradient Penalty(WGAN-GP)technique,records historical environmental information by a recurrent neural network,and evaluates the ice warning levels by a classifier.At each time point,the model diagnoses whether the current sensor failure is due to icing or strong winds.If it is determined that the wire is covered with ice,the icing thickness will be calculated after the wind-induced tension is removed from the ice-wind coupling tension.Our new model was evaluated using data from the power grid in an area with extreme weather.The results show that the proposed model has significant improvements in accuracy compared with traditional models.展开更多
Wire rope inspection robot is an important tool for wire rope condition monitoring and maintenance,which can accurately locate and judge the damage of wire rope.In addition,the wire rope inspection robot can also be u...Wire rope inspection robot is an important tool for wire rope condition monitoring and maintenance,which can accurately locate and judge the damage of wire rope.In addition,the wire rope inspection robot can also be used for cable inspection.First,the crawling structure and crawling mode of the wire rope inspection robot are reviewed,and the characteristics and existing problems of each crawling mode are analyzed separately.Next,the drive mode of the wire rope inspection robot is discussed,the types of commonly used motors are introduced,and the advantages and disadvantages of drive motors and the control modes are compared.Then,the method and principle of the non-destructive detection of the wire rope inspection robot are expounded,and the commonly used detection methods and existing deficiencies are compared.After that,the types of communication modes are compared and analyzed,and the types of wireless communication modes are also introduced.Finally,the current difficult problems of the wire rope inspection robot are summarized,and the future development trend of the wire rope inspection robot is prospected.展开更多
Combining the advantages of high efficiency,low-pressure drop,and large throughput,the pore arrayenhanced tube-in-tube microchannel(PA-TMC) is a promising microreactor for industrial applications.However,most of the m...Combining the advantages of high efficiency,low-pressure drop,and large throughput,the pore arrayenhanced tube-in-tube microchannel(PA-TMC) is a promising microreactor for industrial applications.However,most of the mass transfer takes place in the upstream pore region,while the contribution of the downstream annulus is limited.In this work,helical wires were introduced into the annulus by adhering to the outer surface of the inner tube.Mixing behavior and mass transfer of liquid-liquid twophase flow in PA-TMC with different helical wires have been systematically studied by a combination of experiments and volume of fluid(VOF) method.The introduction of helical wires improves the overall volumetric mass transfer coefficient KLa by up to 133% and the mass transfer efficiency E by up to 117%.The simulation results show that the helical wire brings extra phase mixing regions and increases the specific interface area,while accelerating the fluid flow and expanding the area of enhanced turbulent dissipation rate.Influences of helical wires in various configurations are compared by the comprehensive index I concerning the pressure drop and mass transfer performance simultaneously and a new correlation between KLa and specific energy consumption φ is proposed.This research deepens the understanding of the mixing behavior and mass transfer in the PA-TMCs and provides practical experience for the process intensification of microchannel reactors.展开更多
The deformation of Cu–20 wt.%Fe alloy wires leads to a significant improvement in mechanical properties and a decrease in electrical conductivity.Simultaneous improvements in strength and conductivity were achieved b...The deformation of Cu–20 wt.%Fe alloy wires leads to a significant improvement in mechanical properties and a decrease in electrical conductivity.Simultaneous improvements in strength and conductivity were achieved by intermediate annealing of drawn Cu–20 wt.%Fe wires.As the annealing temperature increased,the strength of Cu–20 wt.%Fe alloy wire decreased monotonically,but the electrical conductivity first increased and then decreased,reaching its peak value after annealing at 500℃.The decrease in strength is related to dislocation recovery and static recrystallization of Cu and Fe phases,and the increase in electrical conductivity mainly results from the aging precipitation of solid solution Fe.After annealing at 500℃,there was no obvious recrystallization of Cu phase,and many of the nano-Fe particles precipitated from Cu matrix.An annealing temperature of 600℃ induced the recrystallization of Cu matrix and an increase in Fe solid solubility,resulting in a decrease in strength and electrical conductivity.Subsequently,the wires annealed at 500℃ were drawn to 2 mm.Compared with those of the continuously drawn Cu–20 wt.%Fe alloy wires,the deformation ability,strength,and electrical conductivity of Cu–20 wt.%Fe alloy wires subjected to intermediate annealing treatment are significantly greater.This is mainly related to the sufficient precipitation of Fe in Cu matrix and the strengthening of refined Fe fibers parallel to the drawing direction.展开更多
A reasonable process plan is an important basis for implementing wire arc additive and subtractive hybrid manufacturing(ASHM),and a new optimization method is proposed.Firstly,the target parts and machining tools are ...A reasonable process plan is an important basis for implementing wire arc additive and subtractive hybrid manufacturing(ASHM),and a new optimization method is proposed.Firstly,the target parts and machining tools are modeled by level set functions.Secondly,the mathematical model of the additive direction optimization problem is established,and an improved particle swarm optimization algorithm is designed to decide the best additive direction.Then,the two-step strategy is used to plan the hybrid manufacturing alternating sequence.The target parts are directly divided into various processing regions;each processing region is optimized based on manufacturability and manufacturing efficiency,and the optimal hybrid manufacturing alternating sequence is obtained by merging some processing regions.Finally,the method is used to outline the process plan of the designed example model and applied to the actual hybrid manufacturing process of the model.The manufacturing result shows that the method can meet the main considerations in hybrid manufacturing.In addition,the degree of automation of process planning is high,and the dependence on manual intervention is low.展开更多
Wire arc additive manufacturing(WAAM)presents a promising approach for fabricating medium-to-large austenitic stainless steel components,which are essential in industries like aerospace,pressure vessels,and heat excha...Wire arc additive manufacturing(WAAM)presents a promising approach for fabricating medium-to-large austenitic stainless steel components,which are essential in industries like aerospace,pressure vessels,and heat exchangers.This research examines the mi-crostructural characteristics and tensile behaviour of SS308L manufactured via the gas metal arc welding-based WAAM(WAAM 308L)process.Tensile tests were conducted at room temperature(RT,25℃),300℃,and 600℃in as-built conditions.The microstructure con-sists primarily of austenite grains with retainedδ-ferrite phases distributed within the austenitic matrix.The ferrite fraction,in terms of fer-rite number(FN),ranged between 2.30 and 4.80 along the build direction from top to bottom.The ferrite fraction in the middle region is 3.60 FN.Tensile strength was higher in the horizontal oriented samples(WAAM 308L-H),while ductility was higher in the vertical ones.Tensile results show a gradual reduction in strength with increasing test temperature,in which significant dynamic strain aging(DSA)is observed at 600℃.The variation in serration behavior between the vertical and horizontal specimens may be attributed to microstructural differences arising from the build orientation.The yield strength(YS),ultimate tensile strength(UTS),and elongation(EL)of WAAM 308L at 600℃were(240±10)MPa,(442±16)MPa,and(54±2.00)%,respectively,in the horizontal orientation(WAAM 308L-H),and(248±9)MPa,(412±19)MPa,and(75±2.80)%,respectively,in the vertical orientation(WAAM 308L-V).Fracture surfaces revealed a transition from ductile dimple fracture at RT and 300℃to a mixed ductile-brittle failure with intergranular facets at 600℃.The research explores the applicability and constraints of WAAM-produced 308L stainless steel in high-temperature conditions,offering crucial in-sights for its use in thermally resistant structural and industrial components.展开更多
Wire arc additive manufacturing(WAAM)is one of the most promising approaches to manufacturing large and complex metal components owing to its low cost and high efficiency.However,pores and coarse columnar grains cause...Wire arc additive manufacturing(WAAM)is one of the most promising approaches to manufacturing large and complex metal components owing to its low cost and high efficiency.However,pores and coarse columnar grains caused by thermal accumulation in WAAM significantly decrease the strength and increase the anisotropy,preventing the achievement of both high strength and isotropy.In this study,the strength and anisotropy of AlMg-Sc-Zr alloys were improved by regulating heat input.The results indicated that as the heat input increased from 60 to 99 J/mm,all the components had lower porosity(lower than 0.04%),the size of the Al_(3)(Sc_(1-x),Zr_(x))phases decreased,and the number density increased.The average grain size gradually decreased,and the grain morphologies transformed from coarse equiaxed grain(CEG)+fine equiaxed grain(FEG)to FEG owing to the increase in Al_(3)(Sc_(1-x),Zr_(x))phases with increasing heat input.After heat treatment at 325℃for 6 h,high-density dispersed Al_(3)Sc phases(<10 nm)precipitated.The alloy possessed the highest strength at 79 J/mm,ultimate tensile strength(UTS)of approximately 423±3 MPa,and in-plane anisotropy of approximately 4.3%.At a heat input of 99 J/mm,the in-plane anisotropy decreased to 1.2%and UTS reached 414±5 MPa.The reduction in the CEG prolonged the crack propagation path,which improved the UTS in the vertical direction and reduced the anisotropy.Theoretical calculations indicated that the main strengthening mechanisms were solid solution and precipitation strengthening.This study lays the theoretical foundations for WAAM-processed high-strength and isotropic Al alloy components.展开更多
Additive manufacturing(AM)technologies,with their high degree of flexibility,enhance material utilization in the fabrication of large magnesium alloy parts,effectively meeting the demands of complex geometries.However...Additive manufacturing(AM)technologies,with their high degree of flexibility,enhance material utilization in the fabrication of large magnesium alloy parts,effectively meeting the demands of complex geometries.However,research on the corrosion resistance of magnesium alloy components produced via AM is currently limited.This study investigates the microstructural and corrosion characteristics of AZ91D magnesium alloy fabricated by wire arc additive manufacturing(WAAM)compared to its cast counterpart.A large-sized AZ91D bulk part was deposited on an AZ31 base plate using a layer-by-layer stacking approach.The results showed that the WAAM AZ91D was featured by obviously refined grains from 228.92μm of the cast one to 52.92μm on the travel direction-through thickness(TD-TT)and 50.07μm on the normal direction-through thickness(ND-TT).The rapid solidification process of WAAM inhibited the formation of β-Mg_(17)Al_(12) phase while promoting the formation of uniformly distributed network of dislocations,the dispersive precipitation of nano Al_(8)Mn_(5) phase,as well as Zn segregation.WAAM AZ91D demonstrated the occurrence of pitting corrosion and inferior corrosion resistance compared to cast AZ91D,attributed to the micro-galvanic corrosion between the α-Mg matrix and Al_(8)Mn_(5) particles and the increased number of grain boundaries.展开更多
Interlayer friction stir processing(FSP)has been proved to be an efective method of enhancing the mechanical properties of wire arc-directed energy deposited(WA-DED)samples.However,the original deposition structure wa...Interlayer friction stir processing(FSP)has been proved to be an efective method of enhancing the mechanical properties of wire arc-directed energy deposited(WA-DED)samples.However,the original deposition structure was still retained in the FSP-WA-DED component besides the processed zone(PZ),thus forming a composite structure.Considering the material utilization and practical service process of the deposited component,more attention should be paid on this special composite structure,but the relevant investigation has not been carried out.In this study,an Al–Mg–Sc alloy was prepared by WA-DED with interlayer FSP treatment,and the composite structure was frstly investigated.Almost all of the pores were eliminated under the pressure efect from the tool shoulder.The grains were further refned with an average size of about 1.2μm in the PZ.Though no severe plastic deformation was involved in the retained WA-DED deposition zone,comparable tensile properties with the PZ sample were obtained in the composite structure.Low ultimate tensile strength(UTS)of 289 MPa and elongation of 3.2%were achieved in the WA-DED sample.After interlayer FSP treatment,the UTS and elongation of the PZ samples were signifcantly increased to 443 MPa and 16.3%,while those in the composite structure remained at relatively high levels of 410 MPa and 13.5%,respectively.Meanwhile,a high fatigue strength of 180 and 130 MPa was obtained in the PZ and composite structure samples,which was clearly higher than that of the WA-DED sample(100 MPa).It is concluded that the defects in traditional WA-DED process can be eliminated in the composite structure after interlayer FSP treatment,resulting in enhanced tensile and fatigue properties,which provides an efective method of improving the mechanical properties of the WA-DED sample.展开更多
基金Project supported by“Unveiled the List of Commanders”Key Core Common Technology Projects of Ji’an,ChinaProject(LJKMZ20220591)supported by the Basic Scientific Research Project of the Education Department of Liaoning Province,ChinaProject(CSTB2023NSCQ-LZX0116)supported by the Natural Science Foundation Joint Fund for Innovation and Development Projects of Chongqing,China。
文摘The ultrafine copper wire with a diameter of 18μm is prepared via cold drawing process from the single crystal downcast billet(Φ8 mm),taking a drawing strain to 12.19.In this paper,in-depth investigation of the microstructure feature,texture evolution,mechanical properties,and electrical conductivity of ultrafine wires ranging fromΦ361μm toΦ18μm is performed.Specially,the microstructure feature and texture type covering the whole longitudinal section of ultrafine wires are elaborately characterized.The results show that the average lamella thickness decreases from 1.63μm to 102 nm during the drawing process.Whereas,inhomogeneous texture evolution across different wire sections was observed.The main texture types of copper wires are comprised of<111>,<001>and<112>orientations.Specifically,the peripheral region is primarily dominated by<111>and<112>,while the central region is dominated by<001>and<111>.As the drawing strain increases,the volume fraction of hard orientation<111>with low Schmid factor increases,where notably higher fraction of<111>is resulted from the consumption of<112>and<001>for the wire ofΦ18μm.For drawn copper wire of 18μm,superior properties are obtained with a tensile strength of 729.8 MPa and an electrical conductivity of 86.9%IACS.Furthermore,it is found that grain strengthening,dislocation strengthening,and texture strengthening are three primary strengthening mechanisms of drawn copper wire,while the dislocation density is the main factor on the reducing of conductivity.
基金supported by the National Natural Science Foundation of China(No.52205360)。
文摘Owing to the lack of matching commercial welding wires,the development of wire arc additive manufacturing(WAAM)for most aluminum alloys is hindered.A wire-powder synchronous arc additive manufacturing(WPAAM)was proposed to prepare the target Al-Si-Mg aluminum alloy.Based on the synchronous deposition of AlSi_(12) wire and pure Mg powder,the deposition width of the WPAAMed thin-wall was increased by 61% compared with that of WAAMed thin-wall using AlSi_(12) wire,and the machining allowance was reduced by 81%.The added Mg powder benefited to form refined equiaxed grains,and reduced the average grain size of the WPAAMed thin-wall to 47.1μm,showing a decrease of 23.8% relatively to that of the WAAMed thin-wall.Besides,Mg reacted with Si to form Mg_(2)Si strengthening phases.The mechanical properties tests showed that the ultimate tensile strength and elongation of the WPAAMed thin-wall increased up to 174.5 MPa and 4.1%,reaching 92% and 60% those of the WAAMed thin-wall,respectively.
文摘BACKGROUND Correcting skeletal class III malocclusion with anterior crossbite in adolescents using only orthodontic treatment poses challenges.This report highlights a novel approach leveraging improved superelastic Ni-Ti alloy wire(ISW)to address these conditions effectively.CASE SUMMARY A 17-year-old male patient presented with the chief complaint of an underbite.The patient was given a diagnosis of skeletal class III malocclusion and anterior crossbite.The orthodontic treatment plan was implemented and did not require teeth extractions or orthognathic surgery.Key interventions involved the app-lication of ISW,intermaxillary elastics,and ISW unilateral multi-bend edgewise archwire.The unique combination of these techniques enabled the correction without the need for extractions or surgery.This approach leverages the advanced biomechanical properties of ISW,including its super-elasticity and shape memory,to enhance treatment efficacy.The treatment lasted 17 months,and major improvements in overjet,overbite,and alignment were achieved.The results were favorable,and stability was discovered during follow-up.CONCLUSION The application of ISW for treating skeletal class III malocclusion with anterior crossbite in a 17-year-old male patient resulted in exceptional outcomes.The treatment led to a marked improvement in the patient’s facial profile and to proper overjet,overbite,and midline alignment.These results were maintained over a one-year follow-up,indicating that a minimally invasive orthodontic approach can effectively address complex skeletal discrepancies in adolescent patients.This case illustrates that with the careful use of advanced orthodontic techniques,major skeletal challenges can be resolved without resorting to surgical procedures.
基金supported by National Natural Science Foundation of China(Grant No.12102219)National Key Research and Development Program of China(Grant No.2022YFB4601900)。
文摘The low accuracy of wire arc additive manufacturing(WAAM)is one of the main factors limiting its development,and is detrimental to the mechanical properties of WAAM structures.This study primarily investigated the effects of wire-feeding directions and positions of the molten pool on the quality and accuracy of unsupported WAAM.First,the three-dimensional(3D)morphology and volume of unsupported rods manufactured with different wirefeeding directions were quantitatively evaluated using a 3D scanning method.The effects of the wire-feeding direction and arc length on the volume and standard deviation of the unsupported rods are then discussed in detail.Finally,the influence of the wire-feeding direction on the quality and accuracy of unsupported WAAM is discussed and revealed by combining the temperature gradients,surface tension,and contact angles.The research revealed that feeding a wire into the high-temperature zone of the molten pool could reduce material spatter and achieve higher precision.The volume of the sample fed into the high-temperature zone was 120%of that fed into the low-temperature zone.This reduced not only the material waste but also the standard deviation of the diameter of the same group of samples.This research is of great significance and value for high-quality unsupported WAAM.
基金funded by the National Natural Science Foundation of China(Grant No.42325503)the Hubei Provincial Natural Science Foundation and the Meteorological Innovation and Development Project of China(Grant Nos.2023AFD096 and 2022CFD122)+1 种基金the Natural Science Foundation of Wuhan(Grant No.2024020901030454)the Beijige Foundation of NJIAS(Grant No.BJG202304)。
文摘Based on comprehensive observations of 20 wire icing events during winter from 2019 to 2021,we investigated the characteristics of the icing properties,the atmospheric boundary layer structure,the raindrop size distribution,and their associated effects on the ice accretion mechanism in the mountainous region of Southwest China.The maximum ice weight was positively correlated with the duration of ice accretion in the mountainous area.The duration of precipitation accounted for less than 20%of the icing period in the mountainous area,with solid-phase hydrometeors being predominant.Icing events,dominated by freezing rain(FR)and mixed rain–graupel(more than 70%),were characterized by glaze or highdensity mixed icing.The relationship between the melting energy and refreezing energy reflected the distribution characteristics of the proportion of FR under mixed-phase precipitation.The intensity of the warm layer and the dominant precipitation phase significantly affected the variations in the microphysical properties of FR.The melting of large dry snowflakes significantly contributed to FR in the mountainous areas,resulting in smaller generalized intercepts and larger mass-weighted mean diameters in the presence of a stronger warm layer.Under a weaker warm layer,the value of the massweighted mean diameter was significantly smaller because of the inability of large solid particles to melt.Finally,FR in the mountainous area dominated the ice weight during the rapid ice accumulation period.A numerical simulation of FR icing on wires effectively revealed the evolution of disaster-causing icing in mountainous areas.
基金financially supported by the Agency for Science,Technology and Research(A*Star),Republic of Singapore,under the Aerospace Consortium Cycle 12“Characterization of the Effect of Wire and Powder Deposited Materials”(No.A1815a0078)。
文摘The feasibility of manufacturing Ti-6Al-4V samples through a combination of laser-aided additive manufacturing with powder(LAAM_(p))and wire(LAAM_(w))was explored.A process study was first conducted to successfully circumvent defects in Ti-6Al-4V deposits for LAAM_(p) and LAAM_(w),respectively.With the optimized process parameters,robust interfaces were achieved between powder/wire deposits and the forged substrate,as well as between powder and wire deposits.Microstructure characterization results revealed the epitaxial prior β grains in the deposited Ti-6Al-4V,wherein the powder deposit was dominated by a finerα′microstructure and the wire deposit was characterized by lamellar α phases.The mechanisms of microstructure formation and correlation with mechanical behavior were analyzed and discussed.The mechanical properties of the interfacial samples can meet the requirements of the relevant Aerospace Material Specifications(AMS 6932)even without post heat treatment.No fracture occurred within the interfacial area,further suggesting the robust interface.The findings of this study highlighted the feasibility of combining LAAM_(p) and LAAM_(w) in the direct manufacturing of Ti-6Al-4V parts in accordance with the required dimensional resolution and deposition rate,together with sound strength and ductility balance in the as-built condition.
基金financially supported by the foundation of the NMPA Key Laboratory for Quality Evaluation of Medical Protective and Implant Devices,the Shandong Provincial Natural Science Foundation(ZR2021MB096)to Huali Niethe Science and Technology Research Project of Shanghai Songjiang District Science and Technology Committee(No.2023SJKWGG063)+4 种基金the Medical Engineering Cross Research Project of Shanghai Jiaotong University(No.YG2022QN074)to Changping Wangthe National Nature Science Foundation of China(No.32371383)the Shanghai 2023“Science and Technology Innovation Action Plan”Biomedical Science and Technology Support Special Project(No.23S31900100)the Foundation of National Center for Translational Medicine(Shanghai)SHU Branch(No.SUITM-202411)to Siyu Nithe Research Center for the Industries of the Future at Westlake University and the Zhejiang Provincial Natural Science Foundation of China(No.2022XHSJJ003)for support.
文摘The Kirschner wire(K-wire)is widely used in orthopedic external fixation due to its versatility and clinical effectiveness.However,a significant challenge associated with its use is the potential for bacterial migration,subsequent infection,and dislodgement as the wire penetrates the skin and bone.This study introduces a novel bioactive material,selenium/calcium silicate(Se/β-CS),achieved by integrating selenium-an essential trace element in the human body-into bioceramic calcium silicate.This integration was accomplished using a combined chemical co-deposition method and redox reaction.Furthermore,a uniform and controllable Se/β-CS coating was applied to the K-wire's surface using the Langmuir-Blodgett technique.This coating gradually releases active components-Si,Ca,and Se-that effectively eliminate bacterial infections and promote osteointegration.The findings of this study offer promising opportunities for the use of robust and multifunctional coating materials on implantable devices,particularly within the fields of orthopedics,transplantation,and surgery.
基金supported by the National Natural Science Foundation of China(NSFC)under Grant Nos.52001313,52130002,52273322,and 52321001IMR Innovation Fund under Grant No.2023-PY05+3 种基金the Natural Science Foundation of Liaoning Province under Grant No.2022-MS-001the China Postdoctoral Science Foundation under Grant No.GZC20232740the Zhongke Technology Achievement Transfer and Transformation Center of Henan Province under Grant No.2024109the Joint Research Project between Chinese Academy of Sciences(CAS)under Grant No.174321KYSB20210002.
文摘Simultaneously improving the strength and electrical conductivity of conducting metallic materials is of great significance,but it still remains a key challenge as the two properties are often mutually exclusive.In this study,we demonstrate a“<111>oriented fibrous grains with ultra-high aspect ratio”strategy for breaking such a conflict in Cu wire,which relies on the distinctive spatial distribution of grain boundaries and the highly consistent hard orientation to play their respective roles in suffering loading and conducting,thereby enabling a separate optimization of both strength and electrical conductivity.Therefore,a processing route was designed,involving directional solidification followed by large drawing deformation,to successfully construct fibrous grains with an ultra-high aspect ratio in 596.7 and ultra-high<111>texture proportion over 97%,which achieves Cu wire with a remarkable combination of yield strength in 482.3 MPa and electrical conductivity in 101.63%IACS.Finally,the mechanisms for high strength and high electrical conductivity were quantitatively discussed.
基金financially supported by National Natural Science Foundation of China(Project No.51878156).
文摘To investigate the performance of utilizing the shape memory effect of SMA(Shape Memory Alloy)wire to generate recovery stress,this paper performed single heating recovery stress tests and reciprocating heating-cooling recovery stress tests on SMA wire under varying initial strain conditions.The effects of various strains and different energized heating methods on the recovery stress of SMA wires were explored in the single heating tests.The SMA wire was strained from 2%to 8%initially,and two distinct heating approaches were employed:one using a large current interval for rapid heating and one using a small current interval for slower heating.The experimental outcomes reveal that during a single heating cycle,the temperature-recovery stress relationship of SMA wire exhibits three distinct stages:the martensite phase stage,the transition stage from martensite to austenite phase,and the austenite phase stage.Notably,the choice of heating method does not influence the maximum recovery stress value,and the correlation between initial strain and maximum recovery stress is predominantly linear.Moreover,conducting the reciprocating temperature rise and fall performance test is important to better simulate the scenario in practical engineering where multiple recovery stress in SMA wires for structural repair.In this test,two temperature cycling methods were studied:interval rise and fall,as well as direct rise and fall.In the case of utilizing the interval temperature rise and fall method,it was observed that the recovery stress associated with cooling was significantly higher than that corresponding to heating at the same temperature.Furthermore,the recovery stress was lower upon subsequent heating than that measured during the previous heating cycle.Based on the experimental results,a prediction model for the temperature-recovery stress relationship has been proposed to simplify numerical calculations.It is hoped that an approximate temperaturerecovery stress curve can be obtained from the parameters of the SMA wire.The calculated values derived from this model show good alignment with the measured values,indicating its reliability.
基金supported by the National Natural Science Foundation of China(No.22422402)National Key Research and Development Program of China(No.2022YFF0705300)Key Research and Development Program of Jiangxi Province(No.20232BBG70004)。
文摘The performance and price of copper-based micro linear products are determined by the diameter uniformity.How to accurately detect the wire diameter of long-length copper based micro linear products without cutting or damage has always been a technical concern for production enterprises.Herein,a novel approach was developed for nondestructive detection of the average diameter at any given segment of a long copper wire by assessing the adsorption capacity of arginine on its surface.The amount of adsorbent on the surface of the copper wire exhibits a positive correlation with the area,which can be detected by extractive electrospray ionization mass spectrometry(EESI-MS)after online elution with ammonia.The experimental results demonstrated that the analysis can be completed within 15 min,with a good linear relationship between copper wires with different diameters and the adsorption capacity of arginine.The linear correlation coefficient R2was 0.995,the relative standard deviation was 1.10%-2.81%,and the detection limit reached 2.5μm(length of segment=4 cm),showing potential applications for facile measurement of the average diameter of various metal wires.
基金financially supported by the National Natural Science Foundation of China(Grant No.52471301)the Fujian Province Transportation Science and Technology Project(Grant No.JC202302)the Zhejiang Provincial Natural Science Foundation of China(Grant No.LY24E090003).
文摘Buckling failure in submarine cables presents a prevalent challenge in ocean engineering.This work aims to explore the buckling behavior of umbilical cables with damaged sheaths subjected to compression and bending cyclic loads.A finite element model is devised,incorporating a singular armor wire,a rigid core,and a damaged sheath.To scrutinize the buckling progression and corresponding deformation,axial compression and bending cyclic loads are introduced.The observations reveal that a reduction in axial compression results in a larger number of cycles before buckling ensues and progressively shifts the buckling position toward the extrados and fixed end.Decreasing the bending radius precipitates a reduction in the buckling cycle number and minimizes the deformation in the armor wire.Furthermore,an empirical model is presented to predict the occurrence of birdcage buckling,providing a means to anticipate buckling events and to estimate the requisite number of cycles leading to buckling.
基金supported by the Science and Technology Project of State Grid Corporation of China(SGXJDK00GYJS2400035).
文摘Ice cover on transmission lines is a significant issue that affects the safe operation of the power system.Accurate calculation of the thickness of wire icing can effectively prevent economic losses caused by ice disasters and reduce the impact of power outages on residents.However,under extreme weather conditions,strong instantaneous wind can cause tension sensors to fail,resulting in significant errors in the calculation of icing thickness in traditional mechanics-based models.In this paper,we propose a dynamic prediction model of wire icing thickness that can adapt to extreme weather environments.The model expands scarce raw data by the Wasserstein Generative Adversarial Network with Gradient Penalty(WGAN-GP)technique,records historical environmental information by a recurrent neural network,and evaluates the ice warning levels by a classifier.At each time point,the model diagnoses whether the current sensor failure is due to icing or strong winds.If it is determined that the wire is covered with ice,the icing thickness will be calculated after the wind-induced tension is removed from the ice-wind coupling tension.Our new model was evaluated using data from the power grid in an area with extreme weather.The results show that the proposed model has significant improvements in accuracy compared with traditional models.
基金the National Natural Science Foundation of China(No.12072362)the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘Wire rope inspection robot is an important tool for wire rope condition monitoring and maintenance,which can accurately locate and judge the damage of wire rope.In addition,the wire rope inspection robot can also be used for cable inspection.First,the crawling structure and crawling mode of the wire rope inspection robot are reviewed,and the characteristics and existing problems of each crawling mode are analyzed separately.Next,the drive mode of the wire rope inspection robot is discussed,the types of commonly used motors are introduced,and the advantages and disadvantages of drive motors and the control modes are compared.Then,the method and principle of the non-destructive detection of the wire rope inspection robot are expounded,and the commonly used detection methods and existing deficiencies are compared.After that,the types of communication modes are compared and analyzed,and the types of wireless communication modes are also introduced.Finally,the current difficult problems of the wire rope inspection robot are summarized,and the future development trend of the wire rope inspection robot is prospected.
基金the National Natural Science Foundation of China(22208320)the Science and Technology Program of Henan Province(212102210044)The Henan Association for Science and Technology Youth Talent Support Program(2022HYTP026).
文摘Combining the advantages of high efficiency,low-pressure drop,and large throughput,the pore arrayenhanced tube-in-tube microchannel(PA-TMC) is a promising microreactor for industrial applications.However,most of the mass transfer takes place in the upstream pore region,while the contribution of the downstream annulus is limited.In this work,helical wires were introduced into the annulus by adhering to the outer surface of the inner tube.Mixing behavior and mass transfer of liquid-liquid twophase flow in PA-TMC with different helical wires have been systematically studied by a combination of experiments and volume of fluid(VOF) method.The introduction of helical wires improves the overall volumetric mass transfer coefficient KLa by up to 133% and the mass transfer efficiency E by up to 117%.The simulation results show that the helical wire brings extra phase mixing regions and increases the specific interface area,while accelerating the fluid flow and expanding the area of enhanced turbulent dissipation rate.Influences of helical wires in various configurations are compared by the comprehensive index I concerning the pressure drop and mass transfer performance simultaneously and a new correlation between KLa and specific energy consumption φ is proposed.This research deepens the understanding of the mixing behavior and mass transfer in the PA-TMCs and provides practical experience for the process intensification of microchannel reactors.
基金support provided by National Natural Science Foundation of China(Nos.52405364 and 52171110)Jiangsu Funding Program for Excellent Postdoctoral Talent+3 种基金JITRI Advanced Materials R&D Co.Ltdsupport by European Union Horizon 2020 Research and Innovation Program(857470)European Regional Development Fund via the Foundation for Polish Science International Research Agenda PLUS program(MAB PLUS/2018/8)The publication was created within the framework of the project of the Minister of Science and Higher Education,Support for the Activities of Centres of Excellence established in Poland under Horizon 2020,under contract No.MEiN/2023/DIR/3795.
文摘The deformation of Cu–20 wt.%Fe alloy wires leads to a significant improvement in mechanical properties and a decrease in electrical conductivity.Simultaneous improvements in strength and conductivity were achieved by intermediate annealing of drawn Cu–20 wt.%Fe wires.As the annealing temperature increased,the strength of Cu–20 wt.%Fe alloy wire decreased monotonically,but the electrical conductivity first increased and then decreased,reaching its peak value after annealing at 500℃.The decrease in strength is related to dislocation recovery and static recrystallization of Cu and Fe phases,and the increase in electrical conductivity mainly results from the aging precipitation of solid solution Fe.After annealing at 500℃,there was no obvious recrystallization of Cu phase,and many of the nano-Fe particles precipitated from Cu matrix.An annealing temperature of 600℃ induced the recrystallization of Cu matrix and an increase in Fe solid solubility,resulting in a decrease in strength and electrical conductivity.Subsequently,the wires annealed at 500℃ were drawn to 2 mm.Compared with those of the continuously drawn Cu–20 wt.%Fe alloy wires,the deformation ability,strength,and electrical conductivity of Cu–20 wt.%Fe alloy wires subjected to intermediate annealing treatment are significantly greater.This is mainly related to the sufficient precipitation of Fe in Cu matrix and the strengthening of refined Fe fibers parallel to the drawing direction.
基金The National Natural Science Foundation of China(No.52305381)the Natural Science Foundation of Jiangsu Province(No.BK20210351)the Fundamental Research Funds for the Central Universities(No.30923011008).
文摘A reasonable process plan is an important basis for implementing wire arc additive and subtractive hybrid manufacturing(ASHM),and a new optimization method is proposed.Firstly,the target parts and machining tools are modeled by level set functions.Secondly,the mathematical model of the additive direction optimization problem is established,and an improved particle swarm optimization algorithm is designed to decide the best additive direction.Then,the two-step strategy is used to plan the hybrid manufacturing alternating sequence.The target parts are directly divided into various processing regions;each processing region is optimized based on manufacturability and manufacturing efficiency,and the optimal hybrid manufacturing alternating sequence is obtained by merging some processing regions.Finally,the method is used to outline the process plan of the designed example model and applied to the actual hybrid manufacturing process of the model.The manufacturing result shows that the method can meet the main considerations in hybrid manufacturing.In addition,the degree of automation of process planning is high,and the dependence on manual intervention is low.
基金supported by the Korea Institute of Energy Technology Evaluation and Planning(KETEP)and the Ministry of Trade,Industry&Energy(MOTIE)of the Republic of Korea program(No.RS-2025-02603127,Innovation Research Center for Zero-carbon Fuel Gas Turbine Design,Manufacture,and Safety).
文摘Wire arc additive manufacturing(WAAM)presents a promising approach for fabricating medium-to-large austenitic stainless steel components,which are essential in industries like aerospace,pressure vessels,and heat exchangers.This research examines the mi-crostructural characteristics and tensile behaviour of SS308L manufactured via the gas metal arc welding-based WAAM(WAAM 308L)process.Tensile tests were conducted at room temperature(RT,25℃),300℃,and 600℃in as-built conditions.The microstructure con-sists primarily of austenite grains with retainedδ-ferrite phases distributed within the austenitic matrix.The ferrite fraction,in terms of fer-rite number(FN),ranged between 2.30 and 4.80 along the build direction from top to bottom.The ferrite fraction in the middle region is 3.60 FN.Tensile strength was higher in the horizontal oriented samples(WAAM 308L-H),while ductility was higher in the vertical ones.Tensile results show a gradual reduction in strength with increasing test temperature,in which significant dynamic strain aging(DSA)is observed at 600℃.The variation in serration behavior between the vertical and horizontal specimens may be attributed to microstructural differences arising from the build orientation.The yield strength(YS),ultimate tensile strength(UTS),and elongation(EL)of WAAM 308L at 600℃were(240±10)MPa,(442±16)MPa,and(54±2.00)%,respectively,in the horizontal orientation(WAAM 308L-H),and(248±9)MPa,(412±19)MPa,and(75±2.80)%,respectively,in the vertical orientation(WAAM 308L-V).Fracture surfaces revealed a transition from ductile dimple fracture at RT and 300℃to a mixed ductile-brittle failure with intergranular facets at 600℃.The research explores the applicability and constraints of WAAM-produced 308L stainless steel in high-temperature conditions,offering crucial in-sights for its use in thermally resistant structural and industrial components.
基金supported by National Key Research and Development Program(Grant No.2024YFB4609700)the National Natural Science Foundation of China(Grant No.52374365)。
文摘Wire arc additive manufacturing(WAAM)is one of the most promising approaches to manufacturing large and complex metal components owing to its low cost and high efficiency.However,pores and coarse columnar grains caused by thermal accumulation in WAAM significantly decrease the strength and increase the anisotropy,preventing the achievement of both high strength and isotropy.In this study,the strength and anisotropy of AlMg-Sc-Zr alloys were improved by regulating heat input.The results indicated that as the heat input increased from 60 to 99 J/mm,all the components had lower porosity(lower than 0.04%),the size of the Al_(3)(Sc_(1-x),Zr_(x))phases decreased,and the number density increased.The average grain size gradually decreased,and the grain morphologies transformed from coarse equiaxed grain(CEG)+fine equiaxed grain(FEG)to FEG owing to the increase in Al_(3)(Sc_(1-x),Zr_(x))phases with increasing heat input.After heat treatment at 325℃for 6 h,high-density dispersed Al_(3)Sc phases(<10 nm)precipitated.The alloy possessed the highest strength at 79 J/mm,ultimate tensile strength(UTS)of approximately 423±3 MPa,and in-plane anisotropy of approximately 4.3%.At a heat input of 99 J/mm,the in-plane anisotropy decreased to 1.2%and UTS reached 414±5 MPa.The reduction in the CEG prolonged the crack propagation path,which improved the UTS in the vertical direction and reduced the anisotropy.Theoretical calculations indicated that the main strengthening mechanisms were solid solution and precipitation strengthening.This study lays the theoretical foundations for WAAM-processed high-strength and isotropic Al alloy components.
基金The National Natural Science Foundations of China(Nos.52071191 and 52471080)are acknowledged for providing the financial support.
文摘Additive manufacturing(AM)technologies,with their high degree of flexibility,enhance material utilization in the fabrication of large magnesium alloy parts,effectively meeting the demands of complex geometries.However,research on the corrosion resistance of magnesium alloy components produced via AM is currently limited.This study investigates the microstructural and corrosion characteristics of AZ91D magnesium alloy fabricated by wire arc additive manufacturing(WAAM)compared to its cast counterpart.A large-sized AZ91D bulk part was deposited on an AZ31 base plate using a layer-by-layer stacking approach.The results showed that the WAAM AZ91D was featured by obviously refined grains from 228.92μm of the cast one to 52.92μm on the travel direction-through thickness(TD-TT)and 50.07μm on the normal direction-through thickness(ND-TT).The rapid solidification process of WAAM inhibited the formation of β-Mg_(17)Al_(12) phase while promoting the formation of uniformly distributed network of dislocations,the dispersive precipitation of nano Al_(8)Mn_(5) phase,as well as Zn segregation.WAAM AZ91D demonstrated the occurrence of pitting corrosion and inferior corrosion resistance compared to cast AZ91D,attributed to the micro-galvanic corrosion between the α-Mg matrix and Al_(8)Mn_(5) particles and the increased number of grain boundaries.
基金supported by the National Natural Science Foundation of China(No.U23A20538)the Fundamental Research Funds for the Universities of Liaoning Province,Shenyang U40 Outstanding Youth Foundation(No.RC230864)+1 种基金the Foundation of CAS Henan Industrial Technology Innovation&Incubation Center(No.2024110)the Natural Science Foundation of Liaoning Province(No.2023-BS-016)。
文摘Interlayer friction stir processing(FSP)has been proved to be an efective method of enhancing the mechanical properties of wire arc-directed energy deposited(WA-DED)samples.However,the original deposition structure was still retained in the FSP-WA-DED component besides the processed zone(PZ),thus forming a composite structure.Considering the material utilization and practical service process of the deposited component,more attention should be paid on this special composite structure,but the relevant investigation has not been carried out.In this study,an Al–Mg–Sc alloy was prepared by WA-DED with interlayer FSP treatment,and the composite structure was frstly investigated.Almost all of the pores were eliminated under the pressure efect from the tool shoulder.The grains were further refned with an average size of about 1.2μm in the PZ.Though no severe plastic deformation was involved in the retained WA-DED deposition zone,comparable tensile properties with the PZ sample were obtained in the composite structure.Low ultimate tensile strength(UTS)of 289 MPa and elongation of 3.2%were achieved in the WA-DED sample.After interlayer FSP treatment,the UTS and elongation of the PZ samples were signifcantly increased to 443 MPa and 16.3%,while those in the composite structure remained at relatively high levels of 410 MPa and 13.5%,respectively.Meanwhile,a high fatigue strength of 180 and 130 MPa was obtained in the PZ and composite structure samples,which was clearly higher than that of the WA-DED sample(100 MPa).It is concluded that the defects in traditional WA-DED process can be eliminated in the composite structure after interlayer FSP treatment,resulting in enhanced tensile and fatigue properties,which provides an efective method of improving the mechanical properties of the WA-DED sample.
