Wire arc additive manufacturing(WAAM)has emerged as a promising approach for fabricating large-scale components.However,conventional WAAM still faces challenges in optimizing microstructural evolution,minimizing addit...Wire arc additive manufacturing(WAAM)has emerged as a promising approach for fabricating large-scale components.However,conventional WAAM still faces challenges in optimizing microstructural evolution,minimizing additive-induced defects,and alleviating residual stress and deformation,all of which are critical for enhancing the mechanical performance of the manufactured parts.Integrating interlayer friction stir processing(FSP)into WAAM significantly enhances the quality of deposited materials.However,numerical simulation research focusing on elucidating the associated thermomechanical coupling mechanisms remains insufficient.A comprehensive numerical model was developed to simulate the thermomechanical coupling behavior in friction stir-assisted WAAM.The influence of post-deposition FSP on the coupled thermomechanical response of the WAAM process was analyzed quantitatively.Moreover,the residual stress distribution and deformation behavior under both single-layer and multilayer deposition conditions were investigated.Thermal analysis of different deposition layers in WAAM and friction stir-assisted WAAM was conducted.Results show that subsequent layer deposition induces partial remelting of the previously solidified layer,whereas FSP does not cause such remelting.Furthermore,thermal stress and deformation analysis confirm that interlayer FSP effectively mitigates residual stresses and distortion in WAAM components,thereby improving their structural integrity and mechanical properties.展开更多
Ti-6Al-4V(Ti64)alloys are widely used in the aerospace and automotive industries owing to their excellent high-temperature mechanical properties.This study investigated the creep behavior of Ti64 samples with ultra-lo...Ti-6Al-4V(Ti64)alloys are widely used in the aerospace and automotive industries owing to their excellent high-temperature mechanical properties.This study investigated the creep behavior of Ti64 samples with ultra-lowβcontent(<1%)fabricated by wire arc additive manufacturing(WAAM)under high-temperature and high-stress conditions.The creep properties of the WAAM Ti64 samples were evaluated at 600°C and 700°C with different stresses,and they were analyzed using electron backscattered diffraction(EBSD)and transmission electron microscopy(TEM).Commercially forged Ti64 samples were used as controls to compare their microstructures.As the stress increased,the degree of recrystallization intensified,leading to finer recrystallized grains.After high-temperature deformation,theβcontent in WAAM samples increased from less than 1%to over 8%.The dislocation density was high at low deformations,and the degree of recrystallization was low,suggesting superior creep resistance of the WAAM samples.The stress exponent,EBSD,and TEM analyses confirmed that dislocation movement primarily governs creep deformation in WAAM Ti64.Conversely,the forged samples exhibited easier deformation,lower dislocation density,higher recrystallization,and inferior creep resistance.This research highlights the impact ofβcontent and microstructure on the creep behavior of Ti64.The WAAM Ti64 with ultra-lowβcontent demonstrates enhanced creep resistance compared to commercially forged samples,primarily due to its unique microstructure with closely interconnectedαphases and lowerβ-phase content.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
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
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
Wire arc additive manufacturing(WAAM)has emerged as a promising technique for producing large-scale metal components,favoured by high deposition rates,flexibility and low cost.Despite its potential,the complexity of W...Wire arc additive manufacturing(WAAM)has emerged as a promising technique for producing large-scale metal components,favoured by high deposition rates,flexibility and low cost.Despite its potential,the complexity of WAAM processes,which involves intricate thermal dynamics,phase transitions,and metallurgical,mechanical,and chemical interactions,presents considerable challenges in final product qualities.Simulation technologies in WAAM have proven invaluable,providing accurate predictions in key areas such as material properties,defect identification,deposit morphology,and residual stress.These predictions play a critical role in optimising manufacturing strategies for the final product.This paper provides a comprehensive review of the simulation techniques applied in WAAM,tracing developments from 2013 to 2023.Initially,it analyses the current challenges faced by simulation methods in three main areas.Subsequently,the review explores the current modelling approaches and the applications of these simulations.Following this,the paper discusses the present state of WAAM simulation,identifying specific issues inherent to WAAM simulation itself.Finally,through a thorough review of existing literature and related analysis,the paper offers future perspectives on potential advancements in WAAM simulation strategies.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
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
The present work investigates the corrosion behaviour of an AA2024 alloy thin wall structure produced by wire arc additive manufacturing(WAAM)with interpass rolling,focussing on the influence of interpass rolling.It i...The present work investigates the corrosion behaviour of an AA2024 alloy thin wall structure produced by wire arc additive manufacturing(WAAM)with interpass rolling,focussing on the influence of interpass rolling.It is found that although interpass rolling does not change the typical configuration of thin wall structure,i.e.melt pool zone(MPZ),melt pool border(MPB)and heat-affected zone(HAZ),the plastic deformation introduced by interpass rolling leads to the variation of grain-stored energy across the structure,which consequently results in the highest corrosion susceptibility of MPB due to its relatively high stored energy.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
The Mg-Gd-Y-Zn-Zr(GWZ)alloy containing a long-period ordered stacking(LPSO)phase fabricated by Wire arc additive manufacturing(WAAM)shows substantial potential in the aerospace and automotive industries.In this work,M...The Mg-Gd-Y-Zn-Zr(GWZ)alloy containing a long-period ordered stacking(LPSO)phase fabricated by Wire arc additive manufacturing(WAAM)shows substantial potential in the aerospace and automotive industries.In this work,Mg-9Gd-4Y-1Zn-0.4Zr(wt%)single-layer and multilayer components with high-forming-quality were fabricated using WAAM based on cold metal transfer(WAAM-CMT).The deposition parameters were optimized,achieving better deposition morphology and surface quality.The layer-by-layer cyclic microstructure includes remelting zone(RMZ)and non-remelting zone(NRZ),which consisted of α-Mg matrix,blocky LPSO phase,and eutectic phase.The average grain size were 26.8μm in RMZ and 39.3μm in NRZ,and the volume fraction of secondary phases was around 8%,remaining consistent across different layers.The coarse-fine-grain alternating structure generated hetero deformation induced(HDI)strengthening,while at the same time caused the fracture occurring between the NRZ and RMZ due to the weak interlayer bonding.The thermally stabilized blocky LPSO phase played an effective role on inhibiting grain growth during the solid-solution treatment.The specimen achieved highest isotropic mechanical properties after optimized heat treatment with yield strength,ultimate tensile strength,and elongation higher than 220 MPa,370 MPa,and 8.0%,respectively.The GWZ alloys fabricated by WAAM with great isotropic strength-ductility-synergy are promising candidates to replace the conventionally cast counterparts.展开更多
Wire arc additive manufacturing(WAAM)technology has been used to fabricate the multi-layer single-pass deposited wall of AZ80M magnesium(Mg)alloy by gas tungsten arc welding.The formability,thermal cycles,microstructu...Wire arc additive manufacturing(WAAM)technology has been used to fabricate the multi-layer single-pass deposited wall of AZ80M magnesium(Mg)alloy by gas tungsten arc welding.The formability,thermal cycles,microstructural evolution and mechanical properties of the WAAM AZ80M Mg alloy were investigated.The results show that there was significant difference in the temperature variation and the geometries between the original several layers and the subsequent deposited layers.Owing to the arc energy input,the interpass temperature rised rapidly and then stabilized at 150℃.As a result,the width of the deposited wall increased and then kept stable.There were obvious differences in the microstructure of the WAAM AZ80M Mg alloy among the top zone,intermediate zone and bottom zone of deposited wall.During the arc deposition process,theβphase of the WAAM AZ80M Mg alloy redissolved due to the cyclic heat accumulation,and then precipitated in the grain boundary.The cyclic heat accumulation also led to weakening of dendrite segregation.From the substrate to the top zone,the hardness of the deposited wall decreased gradually,and the intermediate zone which was the main body of deposited wall had relatively uniform hardness.The tensile properties of the WAAM AZ80M Mg alloy were different between the vertical direction and the horizontal direction.And the maximum ultimate tensile strength of the WAAM AZ80M Mg alloy was 308 MPa which was close to that of the as-extruded AZ80M Mg alloy.展开更多
A graded structural material(GSM)with a material transition from TA15 to TC11 was fabricated by wire arc additive manufacturing(WAAM)method.The grain morphology,chemical composition,microstructure and mechanical prope...A graded structural material(GSM)with a material transition from TA15 to TC11 was fabricated by wire arc additive manufacturing(WAAM)method.The grain morphology,chemical composition,microstructure and mechanical properties of the as-deposited GSM were all characterized to investigate their variations along the deposition direction.The results indicate that from TA15 to TC11,the grain size decreases and a transition from columnar grains to equiaxed grains occurs.The content of alloy element alters greatly within a short distance,and the width of the mutation zone is 800μm.Both TA15 and TC11 regions exhibit basketweave microstructure withα-phase andβ-phase.However,during the transition from TA15 to TC11,theα-lath becomes fine,which leads to an increase in microhardness.The tensile test shows that the bonding strength at the interface is higher than the longitudinal strength of TA15,and the lateral elongation at the interface is higher than that of TA15 and TC11.展开更多
To maximize the benefits of wire arc additive manufacturing(WAAM)processes,the effect of post-deposition heat treatment on the microstructure and mechanical properties of WAAM AZ80M magnesium(Mg)alloy was investigated...To maximize the benefits of wire arc additive manufacturing(WAAM)processes,the effect of post-deposition heat treatment on the microstructure and mechanical properties of WAAM AZ80M magnesium(Mg)alloy was investigated.Three different heat treatment procedures(T4,T5 and T6)were performed.According to the results,after T4 heat treatment,the microsegregation of alloying elements was improved with the eutectic structure dissolved.Samples after T5 heat treatment inherited the net-like distribution of secondary phases similar to the as-deposited sample,where the eutectic structure covering the interdendritic regions and theβ-phase precipitated around the eutectic structure.After T6 heat treatment,the tinyβ-phases re-precipitated from the matrix and distributed in inner and outer of the grains.The hardness distribution of the samples went through T4 and T6 heat treatment was more uniform in comparison to that of T5 heat treated samples.The tensile test showed that the T6 heat treatment improved the strength and ductility,and the anisotropy between horizontal and vertical can be eliminated.Moreover,T4 treated samples exhibited highest ductility.展开更多
Realizing improved strength in composite metallic materials remains a challenge using conventional welding and joining systems due to the generation and development of brittle intermetallic compounds caused by complex...Realizing improved strength in composite metallic materials remains a challenge using conventional welding and joining systems due to the generation and development of brittle intermetallic compounds caused by complex thermal profiles during solidification.Here,wire arc additive manufacturing(WAAM)process was used to fabricate a steel-nickel structural component,whose average tensile strength of 634 MPa significantly exceeded that of feedstock materials(steel,537 MPa and nickel,455 MPa),which has not been reported previously.The as-fabricated sample exhibited hierarchically structural heterogeneity due to the interweaving deposition strategy.The improved mechanical response during tensile testing was due to the inter-locking microstructure forming a strong bond at the interface and solid solutions strengthening from the intermixing of the Fe and Ni increased the interface strength,beyond the sum of parts.The research offers a new route for producing high-quality steel-nickel dissimilar structures and widens the design opportunities of monolithic components,with site-specific properties,for specific structural or functional applications.展开更多
In the paper, the finite element model(FEM) of wire arc additive manufacturing(WAAM) by TIG method was established by the ABAQUS soft, and the phase transformation latent heat was considered in the model. The evolutio...In the paper, the finite element model(FEM) of wire arc additive manufacturing(WAAM) by TIG method was established by the ABAQUS soft, and the phase transformation latent heat was considered in the model. The evolution rules of temperature field at the interlayer with the cooling time of 10 s, 30 s and 50 s were obtained by the model. The WAAM experiment were performed by 5356 aluminum alloy welding wire with φ1.2 mm, and the simulated temperature field were varified by the thermocouple. The result shows that the highest temperature at the molten pool center increases with the increased interlayers at the same interlayer cooling time;the highest temperature drops gradually and the decline is smaller with the increased interlayer cooling time at the same layer. No remelting occurs at the top layer, and at least two remelting times occur in the other layers, resulting in complex temperature field evolution.展开更多
Numerous studies have addressed the advantages of wire arc additive manufacturing for manufacturing aluminum alloys. However, the role of Ti content in aluminum alloys has rarely been discussed. Herein, the effect of ...Numerous studies have addressed the advantages of wire arc additive manufacturing for manufacturing aluminum alloys. However, the role of Ti content in aluminum alloys has rarely been discussed. Herein, the effect of Ti content on the microstructure and properties of Al–7 Si–0.6 Mg alloys was studied. The alloys were deposited via wire arc additive manufacturing and were examined through optical microscopy(OM), scanning electron microscopy(SEM), and electronic universal testing. The results show that the increase of Ti content gradually promotes the increase of the secondary dendrite arm spacing and also has an increasing tendency to form pores defect in the as-deposited alloys. The change of titanium content also affects the difference between horizontal and vertical direction properties of the alloy. The alloy with a Ti content of 0.112 wt% exhibits the best comprehensive properties. There is no difference in its horizontal and vertical direction properties. The tensile strengths, yield strengths, and elongation of this alloy(T6) along the vertical and horizontal axis are 356 and 355 MPa, 307 and308 MPa, and 8.5% and 8.0%, respectively.展开更多
Based on wire arc additive manufacturing(WAAM)technology,AZ31 magnesium alloy in bulk was successfully fabricated,and its microstructure as well as mechanical properties in different planes were observed and analyzed....Based on wire arc additive manufacturing(WAAM)technology,AZ31 magnesium alloy in bulk was successfully fabricated,and its microstructure as well as mechanical properties in different planes were observed and analyzed.The AZ31 magnesium alloy has a similar microstructure in the building direction(Z)and travel direction(X),both of which are equiaxed grains.There are heat-affected zones(HAZs)with coarse grains below the fusion line.The second phase is primarily composed of the Mg17Al12 phase,which is evenly distributed in different directions.In addition,the residual stress varies in different directions.There is no significant difference in the hardness of the AZ31 alloy along the Z and X directions,with the average hardness being 68.4 HV and 67.9 HV,respectively.Even though the specimens’ultimate tensile strength along the travel direction is higher in comparison to that along the building direction,their differences in elongation and yield strength are smaller,indicating that the anisotropy of the mechanical properties of the material is small.展开更多
With a high energy efficiency,low geometric limitation,and low cracking susceptivity to cracks,wire arc additive manufacturing(WAAM)has become an ideal substitute for casting in the manufacturing of load-bearing high ...With a high energy efficiency,low geometric limitation,and low cracking susceptivity to cracks,wire arc additive manufacturing(WAAM)has become an ideal substitute for casting in the manufacturing of load-bearing high strength aluminum components in aerospace industry.Recently,in scientific researches,the room temperature mechanical performance of additive manufactured high strength aluminum alloys has been continuously broken through,and proves these alloys can achieve comparable or even higher properties than the forged counterpart.Since the aluminum components for aerospace usage experience high-low temperature cycling due to the absence of atmosphere protection,the high temperature performances of additive manufactured high strength aluminum alloys are also important.However,few research focuses on that.A special 2319Ag Sc with 0.4 wt.%Ag and 0.2 wt.%Sc addition designed for high temperature application is deposited successfully via cold metal transfer(CMT)based on WAAM.The microstructures and high temperature tensile properties are investigated.The results show that the as-deposited 2319Ag Sc alloy presents an alternate distribution of columnar grains and equiaxed grains with no significant textures.Main second phases are Al_(2)Cu and Al3Sc,while co-growth of Al_(2)Cu and bulk Al_(3)Sc is found on the grain boundary.During manufacturing,nanoscale Al_(2)Cu can precipitate out from the matrix.Ag and Mg form nano-scaleΩphase on the Al_(2)Cu precipitates.At 260℃,average yield strengths in the horizontal direction and vertical direction are 87 MPa±2 MPa,87 MPa±4 MPa,while average ultimate tensile strengths are 140 MPa±7 MPa,141 MPa±11 MPa,and average elongations are 11.0%±2.5%,13.5%±3.0%.Anisotropy in different directions is weak.展开更多
Thermal sprayed Ni-5wt.% Al coating was fabricated on the substrate of 6061-T6 aluminum alloy by twin-wire arc spraying. Experimental results indicated that the average value of bond strength was around 46. 90 MPa, th...Thermal sprayed Ni-5wt.% Al coating was fabricated on the substrate of 6061-T6 aluminum alloy by twin-wire arc spraying. Experimental results indicated that the average value of bond strength was around 46. 90 MPa, the average hardness was 240 HV and the average value of surface roughness was about O. 14 mm. Friction and wear test results showed that the dry friction coefficient of Ni-5wt.% Al coating firstly decreased, and then tended to a slight increase after 200 cycles. In the early abrasion stage, adhesion wear played the key role for wear mechanics of Ni-5wt.% Al coating, but gradually abrasive wear became to replace adhesion wear.展开更多
基金National Key Research and Development Program of China(2022YFB4600902)Shandong Provincial Science Foundation for Outstanding Young Scholars(ZR2024YQ020)。
文摘Wire arc additive manufacturing(WAAM)has emerged as a promising approach for fabricating large-scale components.However,conventional WAAM still faces challenges in optimizing microstructural evolution,minimizing additive-induced defects,and alleviating residual stress and deformation,all of which are critical for enhancing the mechanical performance of the manufactured parts.Integrating interlayer friction stir processing(FSP)into WAAM significantly enhances the quality of deposited materials.However,numerical simulation research focusing on elucidating the associated thermomechanical coupling mechanisms remains insufficient.A comprehensive numerical model was developed to simulate the thermomechanical coupling behavior in friction stir-assisted WAAM.The influence of post-deposition FSP on the coupled thermomechanical response of the WAAM process was analyzed quantitatively.Moreover,the residual stress distribution and deformation behavior under both single-layer and multilayer deposition conditions were investigated.Thermal analysis of different deposition layers in WAAM and friction stir-assisted WAAM was conducted.Results show that subsequent layer deposition induces partial remelting of the previously solidified layer,whereas FSP does not cause such remelting.Furthermore,thermal stress and deformation analysis confirm that interlayer FSP effectively mitigates residual stresses and distortion in WAAM components,thereby improving their structural integrity and mechanical properties.
基金supported by the Frontier Technologies R&D Program of Jiangsu(Grant No.BF2024077)Key Research and Development Program of Jiangsu Province(Grant Nos.BE2022069–1,BE2022069–2)+2 种基金National Funded Postdoctoral Researcher Program(Grant No.GZC20240817)Shui Mu Tsinghua Scholar(Grant No.2024SM038)China Postdoctoral Science Foundation(2025M771345).
文摘Ti-6Al-4V(Ti64)alloys are widely used in the aerospace and automotive industries owing to their excellent high-temperature mechanical properties.This study investigated the creep behavior of Ti64 samples with ultra-lowβcontent(<1%)fabricated by wire arc additive manufacturing(WAAM)under high-temperature and high-stress conditions.The creep properties of the WAAM Ti64 samples were evaluated at 600°C and 700°C with different stresses,and they were analyzed using electron backscattered diffraction(EBSD)and transmission electron microscopy(TEM).Commercially forged Ti64 samples were used as controls to compare their microstructures.As the stress increased,the degree of recrystallization intensified,leading to finer recrystallized grains.After high-temperature deformation,theβcontent in WAAM samples increased from less than 1%to over 8%.The dislocation density was high at low deformations,and the degree of recrystallization was low,suggesting superior creep resistance of the WAAM samples.The stress exponent,EBSD,and TEM analyses confirmed that dislocation movement primarily governs creep deformation in WAAM Ti64.Conversely,the forged samples exhibited easier deformation,lower dislocation density,higher recrystallization,and inferior creep resistance.This research highlights the impact ofβcontent and microstructure on the creep behavior of Ti64.The WAAM Ti64 with ultra-lowβcontent demonstrates enhanced creep resistance compared to commercially forged samples,primarily due to its unique microstructure with closely interconnectedαphases and lowerβ-phase content.
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 in part by China Scholarship Council under Grant 202208200010。
文摘Wire arc additive manufacturing(WAAM)has emerged as a promising technique for producing large-scale metal components,favoured by high deposition rates,flexibility and low cost.Despite its potential,the complexity of WAAM processes,which involves intricate thermal dynamics,phase transitions,and metallurgical,mechanical,and chemical interactions,presents considerable challenges in final product qualities.Simulation technologies in WAAM have proven invaluable,providing accurate predictions in key areas such as material properties,defect identification,deposit morphology,and residual stress.These predictions play a critical role in optimising manufacturing strategies for the final product.This paper provides a comprehensive review of the simulation techniques applied in WAAM,tracing developments from 2013 to 2023.Initially,it analyses the current challenges faced by simulation methods in three main areas.Subsequently,the review explores the current modelling approaches and the applications of these simulations.Following this,the paper discusses the present state of WAAM simulation,identifying specific issues inherent to WAAM simulation itself.Finally,through a thorough review of existing literature and related analysis,the paper offers future perspectives on potential advancements in WAAM simulation strategies.
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.
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 National Natural Science Foundation of China(No.52371065).
文摘The present work investigates the corrosion behaviour of an AA2024 alloy thin wall structure produced by wire arc additive manufacturing(WAAM)with interpass rolling,focussing on the influence of interpass rolling.It is found that although interpass rolling does not change the typical configuration of thin wall structure,i.e.melt pool zone(MPZ),melt pool border(MPB)and heat-affected zone(HAZ),the plastic deformation introduced by interpass rolling leads to the variation of grain-stored energy across the structure,which consequently results in the highest corrosion susceptibility of MPB due to its relatively high stored energy.
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supported by the National Key Research and Development Program of China(No.2021YFB3701004)National Natural Science Foundation of China(No.52071211)Joint Research Center of Advanced Aerospace Technology of Shanghai Academy of Spaceflight Technology-Shanghai Jiao Tong University(No.USCAST2020-1).
文摘The Mg-Gd-Y-Zn-Zr(GWZ)alloy containing a long-period ordered stacking(LPSO)phase fabricated by Wire arc additive manufacturing(WAAM)shows substantial potential in the aerospace and automotive industries.In this work,Mg-9Gd-4Y-1Zn-0.4Zr(wt%)single-layer and multilayer components with high-forming-quality were fabricated using WAAM based on cold metal transfer(WAAM-CMT).The deposition parameters were optimized,achieving better deposition morphology and surface quality.The layer-by-layer cyclic microstructure includes remelting zone(RMZ)and non-remelting zone(NRZ),which consisted of α-Mg matrix,blocky LPSO phase,and eutectic phase.The average grain size were 26.8μm in RMZ and 39.3μm in NRZ,and the volume fraction of secondary phases was around 8%,remaining consistent across different layers.The coarse-fine-grain alternating structure generated hetero deformation induced(HDI)strengthening,while at the same time caused the fracture occurring between the NRZ and RMZ due to the weak interlayer bonding.The thermally stabilized blocky LPSO phase played an effective role on inhibiting grain growth during the solid-solution treatment.The specimen achieved highest isotropic mechanical properties after optimized heat treatment with yield strength,ultimate tensile strength,and elongation higher than 220 MPa,370 MPa,and 8.0%,respectively.The GWZ alloys fabricated by WAAM with great isotropic strength-ductility-synergy are promising candidates to replace the conventionally cast counterparts.
基金This work was supported by the China Scholarship Coun-cil(No.201907000039)the national key research and devel-opment plan of China(grant number 2017YFB0305905)the Doctoral Innovation Fund Program of Southwest Jiaotong University(No.D-CX201830).
文摘Wire arc additive manufacturing(WAAM)technology has been used to fabricate the multi-layer single-pass deposited wall of AZ80M magnesium(Mg)alloy by gas tungsten arc welding.The formability,thermal cycles,microstructural evolution and mechanical properties of the WAAM AZ80M Mg alloy were investigated.The results show that there was significant difference in the temperature variation and the geometries between the original several layers and the subsequent deposited layers.Owing to the arc energy input,the interpass temperature rised rapidly and then stabilized at 150℃.As a result,the width of the deposited wall increased and then kept stable.There were obvious differences in the microstructure of the WAAM AZ80M Mg alloy among the top zone,intermediate zone and bottom zone of deposited wall.During the arc deposition process,theβphase of the WAAM AZ80M Mg alloy redissolved due to the cyclic heat accumulation,and then precipitated in the grain boundary.The cyclic heat accumulation also led to weakening of dendrite segregation.From the substrate to the top zone,the hardness of the deposited wall decreased gradually,and the intermediate zone which was the main body of deposited wall had relatively uniform hardness.The tensile properties of the WAAM AZ80M Mg alloy were different between the vertical direction and the horizontal direction.And the maximum ultimate tensile strength of the WAAM AZ80M Mg alloy was 308 MPa which was close to that of the as-extruded AZ80M Mg alloy.
基金financial supports from the National Natural Science Foundation of China(Nos.51875041,51875042)。
文摘A graded structural material(GSM)with a material transition from TA15 to TC11 was fabricated by wire arc additive manufacturing(WAAM)method.The grain morphology,chemical composition,microstructure and mechanical properties of the as-deposited GSM were all characterized to investigate their variations along the deposition direction.The results indicate that from TA15 to TC11,the grain size decreases and a transition from columnar grains to equiaxed grains occurs.The content of alloy element alters greatly within a short distance,and the width of the mutation zone is 800μm.Both TA15 and TC11 regions exhibit basketweave microstructure withα-phase andβ-phase.However,during the transition from TA15 to TC11,theα-lath becomes fine,which leads to an increase in microhardness.The tensile test shows that the bonding strength at the interface is higher than the longitudinal strength of TA15,and the lateral elongation at the interface is higher than that of TA15 and TC11.
基金the China Scholarship Council[grant numbers:201907000039],the National Key Research and Development Plan of China[grant number 2017YFB0305905]The authors acknowledge the financial support from the 2020 open projects[grant numbers:KLATM202003]of Key laboratory of Advanced Technologies of Materials,Ministry of Education China,Southwest Jiaotong University。
文摘To maximize the benefits of wire arc additive manufacturing(WAAM)processes,the effect of post-deposition heat treatment on the microstructure and mechanical properties of WAAM AZ80M magnesium(Mg)alloy was investigated.Three different heat treatment procedures(T4,T5 and T6)were performed.According to the results,after T4 heat treatment,the microsegregation of alloying elements was improved with the eutectic structure dissolved.Samples after T5 heat treatment inherited the net-like distribution of secondary phases similar to the as-deposited sample,where the eutectic structure covering the interdendritic regions and theβ-phase precipitated around the eutectic structure.After T6 heat treatment,the tinyβ-phases re-precipitated from the matrix and distributed in inner and outer of the grains.The hardness distribution of the samples went through T4 and T6 heat treatment was more uniform in comparison to that of T5 heat treated samples.The tensile test showed that the T6 heat treatment improved the strength and ductility,and the anisotropy between horizontal and vertical can be eliminated.Moreover,T4 treated samples exhibited highest ductility.
基金carried out at the Welding Engineering Research Group,University of Wollongong,and it was supported by China Scholarship Council(No.201506680056)the National Natural Science Foundation of China(No.51805085)。
文摘Realizing improved strength in composite metallic materials remains a challenge using conventional welding and joining systems due to the generation and development of brittle intermetallic compounds caused by complex thermal profiles during solidification.Here,wire arc additive manufacturing(WAAM)process was used to fabricate a steel-nickel structural component,whose average tensile strength of 634 MPa significantly exceeded that of feedstock materials(steel,537 MPa and nickel,455 MPa),which has not been reported previously.The as-fabricated sample exhibited hierarchically structural heterogeneity due to the interweaving deposition strategy.The improved mechanical response during tensile testing was due to the inter-locking microstructure forming a strong bond at the interface and solid solutions strengthening from the intermixing of the Fe and Ni increased the interface strength,beyond the sum of parts.The research offers a new route for producing high-quality steel-nickel dissimilar structures and widens the design opportunities of monolithic components,with site-specific properties,for specific structural or functional applications.
基金This work was supported by the National Natural Science Foundation of China(Grant No.51905423)Natural.Science Basic Research Plan in Shaanxi Province of China(Grant No.2021JM338)+1 种基金China Scholarship Council(Grant No.201908610042)Application Technology R&D Project of Beilin District(GX2102).
文摘In the paper, the finite element model(FEM) of wire arc additive manufacturing(WAAM) by TIG method was established by the ABAQUS soft, and the phase transformation latent heat was considered in the model. The evolution rules of temperature field at the interlayer with the cooling time of 10 s, 30 s and 50 s were obtained by the model. The WAAM experiment were performed by 5356 aluminum alloy welding wire with φ1.2 mm, and the simulated temperature field were varified by the thermocouple. The result shows that the highest temperature at the molten pool center increases with the increased interlayers at the same interlayer cooling time;the highest temperature drops gradually and the decline is smaller with the increased interlayer cooling time at the same layer. No remelting occurs at the top layer, and at least two remelting times occur in the other layers, resulting in complex temperature field evolution.
基金financially supported by the National Key R&D Program of China(No.2018YFB1106300-5)。
文摘Numerous studies have addressed the advantages of wire arc additive manufacturing for manufacturing aluminum alloys. However, the role of Ti content in aluminum alloys has rarely been discussed. Herein, the effect of Ti content on the microstructure and properties of Al–7 Si–0.6 Mg alloys was studied. The alloys were deposited via wire arc additive manufacturing and were examined through optical microscopy(OM), scanning electron microscopy(SEM), and electronic universal testing. The results show that the increase of Ti content gradually promotes the increase of the secondary dendrite arm spacing and also has an increasing tendency to form pores defect in the as-deposited alloys. The change of titanium content also affects the difference between horizontal and vertical direction properties of the alloy. The alloy with a Ti content of 0.112 wt% exhibits the best comprehensive properties. There is no difference in its horizontal and vertical direction properties. The tensile strengths, yield strengths, and elongation of this alloy(T6) along the vertical and horizontal axis are 356 and 355 MPa, 307 and308 MPa, and 8.5% and 8.0%, respectively.
基金support from the International Science and Technology Cooperation Program of Shaanxi Province(No.2023-GHZD-50)Projects of Major Innovation Platforms for Scientific and Technological and Local Transformation of Scientific and Technological Achievements of Xi'an(No.20GXSF0003)+1 种基金Projects of Major Scientific and Technological Achievements Local Transformation of Xi'an(No.2022JH-ZDZH-0039)the Higher Education Institution Discipline Innovation and Intelligence Base of Shaanxi Province(No.S2021-ZCGXYZ-0011).
文摘Based on wire arc additive manufacturing(WAAM)technology,AZ31 magnesium alloy in bulk was successfully fabricated,and its microstructure as well as mechanical properties in different planes were observed and analyzed.The AZ31 magnesium alloy has a similar microstructure in the building direction(Z)and travel direction(X),both of which are equiaxed grains.There are heat-affected zones(HAZs)with coarse grains below the fusion line.The second phase is primarily composed of the Mg17Al12 phase,which is evenly distributed in different directions.In addition,the residual stress varies in different directions.There is no significant difference in the hardness of the AZ31 alloy along the Z and X directions,with the average hardness being 68.4 HV and 67.9 HV,respectively.Even though the specimens’ultimate tensile strength along the travel direction is higher in comparison to that along the building direction,their differences in elongation and yield strength are smaller,indicating that the anisotropy of the mechanical properties of the material is small.
基金the National Natural Science Foundation of China(Grant No.U21B2080,52305351,52275324)the China Postdoctoral Science Foundation(Grant No.2023M730838)+1 种基金the Heilongjiang Provincial Postdoctoral Science Foundation(Grant No.LBH-Z22128)the Natural Science Foundation of Heilongjiang Province(Grant No.LH2023E039).
文摘With a high energy efficiency,low geometric limitation,and low cracking susceptivity to cracks,wire arc additive manufacturing(WAAM)has become an ideal substitute for casting in the manufacturing of load-bearing high strength aluminum components in aerospace industry.Recently,in scientific researches,the room temperature mechanical performance of additive manufactured high strength aluminum alloys has been continuously broken through,and proves these alloys can achieve comparable or even higher properties than the forged counterpart.Since the aluminum components for aerospace usage experience high-low temperature cycling due to the absence of atmosphere protection,the high temperature performances of additive manufactured high strength aluminum alloys are also important.However,few research focuses on that.A special 2319Ag Sc with 0.4 wt.%Ag and 0.2 wt.%Sc addition designed for high temperature application is deposited successfully via cold metal transfer(CMT)based on WAAM.The microstructures and high temperature tensile properties are investigated.The results show that the as-deposited 2319Ag Sc alloy presents an alternate distribution of columnar grains and equiaxed grains with no significant textures.Main second phases are Al_(2)Cu and Al3Sc,while co-growth of Al_(2)Cu and bulk Al_(3)Sc is found on the grain boundary.During manufacturing,nanoscale Al_(2)Cu can precipitate out from the matrix.Ag and Mg form nano-scaleΩphase on the Al_(2)Cu precipitates.At 260℃,average yield strengths in the horizontal direction and vertical direction are 87 MPa±2 MPa,87 MPa±4 MPa,while average ultimate tensile strengths are 140 MPa±7 MPa,141 MPa±11 MPa,and average elongations are 11.0%±2.5%,13.5%±3.0%.Anisotropy in different directions is weak.
文摘Thermal sprayed Ni-5wt.% Al coating was fabricated on the substrate of 6061-T6 aluminum alloy by twin-wire arc spraying. Experimental results indicated that the average value of bond strength was around 46. 90 MPa, the average hardness was 240 HV and the average value of surface roughness was about O. 14 mm. Friction and wear test results showed that the dry friction coefficient of Ni-5wt.% Al coating firstly decreased, and then tended to a slight increase after 200 cycles. In the early abrasion stage, adhesion wear played the key role for wear mechanics of Ni-5wt.% Al coating, but gradually abrasive wear became to replace adhesion wear.
