The fabrication of 304L stainless welding wires with a diameter 1.6 mm by using electrochemical cold drawing(ECD)of bars with a diameter of 5.6 mm was investigated,as well as that via traditional cold drawing(TCD)for ...The fabrication of 304L stainless welding wires with a diameter 1.6 mm by using electrochemical cold drawing(ECD)of bars with a diameter of 5.6 mm was investigated,as well as that via traditional cold drawing(TCD)for comparison.The results indicated that the dilute H_(2)SO_(4)aqueous solution was an appropriate electrolyte for ECD,and increasing the H_(2)SO_(4)concentration and current density within a range improved the corrosion rate and uniformity,leading to an easier and more coordinated deformation through uniformly distributing geometrically necessary dislocations and curved large-angle grain boundaries,and decreasing their density,and thus,an enhanced electrochemical plasticization(EP).Under the optimized electrochemical parameters(0.5 mol L^(-1)H_(2)SO_(4)electrolyte and current density of 12.2 mA cm^(-2)),the average cumulative reduction rate required for annealing was up to~34%,obviously higher than~20%of TCD due to the decreased work-hardening from the EP,so that the number of annealing was significantly reduced from 10 of TCD to 5,when the drawing pass was 23.In addition,the surface of the ECD wire was distinctly smoother and brighter than that of the TCD one.These findings confirm the large potential in engineering applications of the ECD technology based on the EP effect.展开更多
High entropy alloys(HEAs)have recently attracted significant attention due to their exceptional mechanical properties and potential applications across various fields.Friction stir welding and processing(FSW/P),as not...High entropy alloys(HEAs)have recently attracted significant attention due to their exceptional mechanical properties and potential applications across various fields.Friction stir welding and processing(FSW/P),as notable solid-state welding and processing techniques,have been proved effectiveness in enhancing microstructures and mechanical properties of HEAs.This review article summarizes the current status of FSW/P of HEAs.The welding materials and conditions used for FSW/P in HEAs are reviewed and discussed.The effects of FSW/P on the evolutions of grain structure,texture,dislocation,and secondary phase for different HEAs are highlighted.Furthermore,the influences of FSW/P on the mechanical properties of various HEAs are analyzed.Finally,potential applications,challenges,and future directions of FSW/P in HEAs are forecasted.Overall,FSW/P enable to refine grains of HEAs through dynamic recrystallization and to activate diverse deformation mechanisms of HEAs through tailoring phase structures,thereby significantly improving the strength,hardness,and ductility of both single-and dual-phase HEAs.Future progress in this field will rely on comprehensive optimization of processing parameters and alloy composition,integration of multi-scale modeling with advanced characterization for in-depth exploration of microstructural mechanisms,systematic evaluation of functional properties,and effective bridging of the gap between laboratory research and industrial application.The review aims to provide an overview of recent advancements in the FSW/P of HEAs and encourage further research in this area.展开更多
In order to obtain good welding quality, it is necessary to apply quality control because there are many influencing factors in laser welding process. The key to realize welding quality control is to obtain the qualit...In order to obtain good welding quality, it is necessary to apply quality control because there are many influencing factors in laser welding process. The key to realize welding quality control is to obtain the quality information. Abundant weld quality information is contained in weld pool and keyhole. Aiming at Nd：YAG laser welding of stainless steel, a coaxial visual sensing system was constructed. The images of weld pool and keyhole were obtained. Based on the gray character of weld pool and keyhole in images, an image processing algorithm was designed. The search start point and search criteria of weld pool and keyhole edge were determined respectively.展开更多
Dissimilar AZ31B magnesium alloy and DC56D steel were welded via AA1060 aluminum alloy by magnetic pulse welding.The effects of primary and secondary welding processes on the welded interface were comparatively invest...Dissimilar AZ31B magnesium alloy and DC56D steel were welded via AA1060 aluminum alloy by magnetic pulse welding.The effects of primary and secondary welding processes on the welded interface were comparatively investigated.Macroscopic morphology,microstructure,and interfacial structure of the joints were analyzed using scanning electron microscope,energy dispersive spectrometer,and X-ray diffractometer(XRD).The results show that magnetic pulse welding of dissimilar Mg/Fe metals is achieved using an Al interlayer,which acts as a bridge for deformation and diffusion.Specifically,the AZ31B/AA1060 interface exhibits a typical wavy morphology,and a transition zone exists at the joint interface,which may result in an extremely complex microstructure.The microstructure of this transition zone differs from that of AZ31B magnesium and 1060 Al alloys,and it is identified as brittle intermetallic compounds(IMCs)Al_(3)Mg_(2) and Al_(12)Mg_(17).The transition zone is mainly distributed on the Al side,with the maximum thickness of Al-side transition layer reaching approximately 13.53μm.Incomplete melting layers with varying thicknesses are observed at the primary weld interface,while micron-sized hole defects appear in the transition zone of the secondary weld interface.The AA1060/DC56D interface is mainly straight,with only a small number of discontinuous transition zones distributed intermittently along the interface.These transition zones are characterized by the presence of the brittle IMC FeAl_(3),with a maximum thickness of about 4μm.展开更多
Agricultural Products Processing and Storage(ISSN 3059-4510,Owner:Hunan Academy of Agricultural Sciences,China.Production and hosting:Springer Nature)is an international,peer-reviewed open access journal with the aim ...Agricultural Products Processing and Storage(ISSN 3059-4510,Owner:Hunan Academy of Agricultural Sciences,China.Production and hosting:Springer Nature)is an international,peer-reviewed open access journal with the aim to offer a platform for the rapid dissemination of significant,novel,and high-impact research in the fields of agricultural product processing science,technology,engineering,and nutrition.Additionally,supplemental issues are curated and published to facilitate in-depth discussions on special topics.展开更多
Joining dissimilar materials encounters significant engineering challenges due to the contrast in material properties that makes conventional welding not feasible.Magnetic Pulse Welding(MPW)offers a solidstate joining...Joining dissimilar materials encounters significant engineering challenges due to the contrast in material properties that makes conventional welding not feasible.Magnetic Pulse Welding(MPW)offers a solidstate joining technique that overcomes these issues by using impact to create strong bonds without melting the substrate materials.This study investigates the weldability of aluminum alloy Al-5754 with Al-7075 and MARS 380 steel,used in armouring solutions of defense systems,by the use of MPW.In this work,weldability windows are investigated by varying standoff distances between the coating material and its substrate(0.25-4.5 mm)and discharge energies(5-13 kJ)with both O-shape and U-shape inductors.Mechanical strength of the welded joints were assessed through single lap shear tests,identifying optimal welding parameters.Then,the velocity profiles of the flyer plates were measured using heterodyne velocimetry to understand the dynamics of the impact.Then,substructures assembled with the optimal welding conditions were subjected to ballistic testing using 7.62 mm×51 mm NATO and 9 mm×19 mm Parabellum munitions to evaluate the resilience of the welds under ballistic impact.The outcomes demonstrate that MPW effectively joins Al-5754 with both Al-7075 and MARS 380,producing robust welds capable of withstanding ballistic impacts under certain conditions.This research advances the application of MPW in lightweight ballistic protection of defense systems,contributing to the development of more resilient and lighter protective structures.展开更多
The hot compression deformation behavior of Mg-6Zn-1Mn-0.5Ca(ZM61-0.5Ca)and Mg-6Zn-1Mn-2Sn-0.5Ca(ZMT612-0.5Ca)alloys was investigated at deformation temperatures ranging from 250℃to 400℃and strain rates varying from...The hot compression deformation behavior of Mg-6Zn-1Mn-0.5Ca(ZM61-0.5Ca)and Mg-6Zn-1Mn-2Sn-0.5Ca(ZMT612-0.5Ca)alloys was investigated at deformation temperatures ranging from 250℃to 400℃and strain rates varying from 0.001 s^(-1) to 1 s^(-1).The results show that the addition of Sn promotes dynamic recrystallization(DRX),and CaMgSn phases can act as nucleation sites during the compression deformation.Flow stress increases with increasing the strain rate and decreasing the temperature.Both the ZM61-0.5Ca and ZMT612-0.5Ca alloys exhibit obvious DRX characteristics.CaMgSn phases can effectively inhibit dislocation motion with the addition of Sn,thus increasing the peak fl ow stress of the alloy.The addition of Sn increases the hot deformation activation energy of the ZM61-0.5Ca alloy from 199.654 kJ/mol to 276.649 kJ/mol,thus improving the thermal stability of the alloy.For the ZMT612-0.5Ca alloy,the optimal hot deformation parameters are determined to be a deformation temperature range of 350–400℃and a strain rate range of 0.001–0.01 s^(-1).展开更多
Agricultural Products Processing and Storage(ISSN 3059-4510,Owner:Hunan Academy of Agricultural Sciences,China.Production and hosting:Springer Nature)is an international,peer-reviewed open access journal with the aim ...Agricultural Products Processing and Storage(ISSN 3059-4510,Owner:Hunan Academy of Agricultural Sciences,China.Production and hosting:Springer Nature)is an international,peer-reviewed open access journal with the aim to offer a platform for the rapid dissemination of signifi cant,novel,and high-impact research in the fi elds of agricultural product processing science,technology,engineering,and nutrition.Additionally,supplemental issues are curated and published to facilitate in-depth discussions on special topics.展开更多
In this study,a 1400 MPa-grade ultra-high-strength steel thin-plate butt-welded joint was selected as the research object,and the joint was fabricated using the metal inert gas(MIG)welding process with ER307Si filler ...In this study,a 1400 MPa-grade ultra-high-strength steel thin-plate butt-welded joint was selected as the research object,and the joint was fabricated using the metal inert gas(MIG)welding process with ER307Si filler wire.Residual stress distributions were measured via the hole-drilling method,while micro-hardness was assessed using a micro-hardness tester.Simultaneously,both transverse shrinkage and angular distortion of the welded joint were experimentally determined.According to the hardness distribution of the joint,a thermalmetallurgical-mechanical finite element model was developed based on SYSWELD software platform.This model incorporates solid-state phase transformations(SSPT)and softening effect in the HAZ,as well as strain hardening and annealing behaviors in the weld metal.The temperature field,residual stress distribution,and welding deformation of single-pass butt-welded joint were simulated by the developed computational method.The simulation results were validated against experimental measurements,confirming the accuracy and reliability of the proposed computational approach.Furthermore,based on the numerical results,the influence mechanisms of SSPT and material softening on residual stress and deformation were analyzed.The findings indicate that SSPT exhibits considerable influences on the magnitude and distribution of welding residual stress.It reduces the peak longitudinal residual stress from 1620 MPa to 1350 MPa and increases the peak transverse residual stress from 350 MPa to 402 MPa.The results also manifest that the softening effect further reduces the peak longitudinal residual stress by 300 MPa,while exhibits minor effect on transverse residual stress.However,the results show that neither the SSPT nor the softening effect presents obvious influence on welding deformation.展开更多
The composite structures/components made by friction stir lap welding(FSLW)of Mg alloy sheet and Al alloy sheet are of wide application potentials in the manufacturing sector of transportation vehicles.To further impr...The composite structures/components made by friction stir lap welding(FSLW)of Mg alloy sheet and Al alloy sheet are of wide application potentials in the manufacturing sector of transportation vehicles.To further improve the joint quality,the ultrasonic vibration(UV)is exerted in FSLW,and the UV enhanced FSLW(UVeFSLW)was developed for making Mg-to-Al dissimilar joints.The numerical analysis and experimental investigation were combined to study the process mechanism in Mg/Al UVeFSLW.An equation related to the temperature and strain rate was derived to calculate the grain size at different locations of the weld nugget zone,and the effect of grain size distribution on the threshold thermal stress was included,so that the prediction accuracy of flow stress was further improved.With such modified constitutive equation,the numerical simulation was conducted to compare the heat generation,temperature profiles and material flow behaviors in Mg/Al UVeFSLW/FSLW processes.It was found that the exerted UV decreased the temperature at two checking points on the tool/workpiece interface from 707/671 K in FSLW to 689/660 K in UVeFSLW,which suppressed the IMCs thickness at Mg-Al interface from 1.7μm in FSLW to 1.1μm in UVeFSLW.The exerted UV increased the horizontal materials flow ability,and decreased the upward flow ability,which resulted in the increase of effective sheet thickness/effective lap width from 2.01/3.70 mm in FSLW to 2.04/4.84 mm in UVeFSLW.Therefore,the ultrasonic vibration improved the tensile shear strength of Mg-to-Al lap joints by 18%.展开更多
Low heat input welding is widely used in the industry.The microstructure and toughness of the welded joints under low heat input conditions have received less attention than those under high heat input.The impact toug...Low heat input welding is widely used in the industry.The microstructure and toughness of the welded joints under low heat input conditions have received less attention than those under high heat input.The impact toughness,microstructure and failure mechanisms of the coarse-grain heat-affected zone(CGHAZ)in a micro-alloyed steel were investigated by welding thermal simulation with the heat input ranging from 15 to 65 kJ/cm.The impact toughness of CGHAZ is highly sensitive to variations in low heat input.The failure mechanisms were discussed from the viewpoints of micro-voids formation and micro-cracks propagation.The micro-voids are preferred to be formed and grow at soft phase of grain boundary ferrite(GBF).At the heat inputs no more than 22 kJ/cm,martensite was dominantly formed,and the micro-cracks initiated from the GBF were propagated into the grain interiors,leading to the brittle fracture and low toughness.When the heat input was increased to 31.2 kJ/cm,granular bainite became the dominant constitute,causing cracks to deflect away from GBF and propagate into prior austenite grains.The high density high-angle and low-angle grain boundaries and the presence of retained austenite,effectively restricted the crack propagation,resulting in ductile fracture behavior and enhanced toughness.High heat input(62.3 kJ/cm)promoted coarse GBF formation,providing continuous paths for microcrack propagation.This direct intergranular crack progression caused brittle fracture and low toughness.Industrial cold cracking in the CGHAZ can thus be controlled by heat input optimization to maximize toughness.展开更多
A phase-field model including magnetic field induced dendrite fragmentation was established and applied to the cases with different initial crystal nuclear positions for AA5754 aluminum alloy electromagnetic laser bea...A phase-field model including magnetic field induced dendrite fragmentation was established and applied to the cases with different initial crystal nuclear positions for AA5754 aluminum alloy electromagnetic laser beam welding.Compare the calculated results that include dendrite fragmentation caused by the thermal electromagnetic Lorentz force with the results that consider only the thermal electromagnetic Lorentz force,without fragmentation,at the characteristic time instants.Both in the early and late stages,the small fragmentation at the dendrite tip promotes the number of higher-order branches and their growth,especially in the direction perpendicular to the solidification.The later stage fragmentation has the possibility of breaking one grain into several,which verifies the possibility of grain refinement caused by dendrite fragmentation.The fracture surface caused by fragmentation also makes more solid-liquid interfaces and their growth.In addition,the cases with different initial nuclear positions were compared.The grain growth in the low-temperature zone can be inhibited by the equiaxed grains'fragmentation at the high-temperature area(179.8μm^(2) and 14.7% start at the center,115.4μm^(2) and 9.4% start at the high-temperature corner,134.3μm^(2) and 10.9%start at the low-temperature corner),which is another kind of grain refinement by the dendrite fragmentation.This kind of inhibition effect on grain growth in the low-temperature region will be enhanced with the increasing time interval between the two crystal nuclei’appearance(179.8μm^(2) and 14.7%when virtual grains appear at t=4.3803 s and t=4.3803 s,134.3μm^(2) and 10.9%at t=4.0977 s and t=3.9564 s,and 115.4μm^(2) and 9.4%at t=3.8151 s and t=3.5325 s).展开更多
This study investigated the effects of xu-argument-based continuation writing on learners’processing of source texts.Seventy-five participants were randomly assigned to three conditions:(1)continuation writing,(2)sum...This study investigated the effects of xu-argument-based continuation writing on learners’processing of source texts.Seventy-five participants were randomly assigned to three conditions:(1)continuation writing,(2)summary writing,or(3)reading comprehension.Eye-tracking data were collected during reading,measuring early(first fixation duration,first pass duration)and late(go-past time,total fixation duration)eye movements.During writing,source-text rereading was tracked via fixation counts and durations.Results showed that task type did not affect initial lexical access,as first fixation duration showed no group differences.However,both production groups exhibited significantly longer first pass durations than the reading comprehension group.Late measures revealed a gradient pattern:the continuation writing group spent significantly longer gopast time and total fixation duration than the summary writing group,which exceeded the reading comprehension group.This indicates that continuation tasks promoted deeper cognitive engagement during reading.During writing,the continuation writing group spent more time rereading the source text with higher fixation counts than the summary writing group.These findings suggest that continuation writing triggers more intensive reader-text interaction during pre-writing and enhances comprehension-production coupling through sustained attention to input during writing.This study sheds light on the cognitive mechanisms underlying the theoretical and pedagogical value of xu-argument.展开更多
Suancai has a lengthy history and a wide range of categories,which has some influence on the pickled diet culture around the world.Suancai production is transitioning to a large-scale,standardized production due to th...Suancai has a lengthy history and a wide range of categories,which has some influence on the pickled diet culture around the world.Suancai production is transitioning to a large-scale,standardized production due to the growth of the market.It has a unique flavor and is rich in nutrients,and its abundance of free amino acids,vitamins and phenolics has many positive effects on the human body.This review gives the types and history of suancai,as well as its impact on the world’s pickled culture.The changes in nutritional composition and flavor of suancai during fermentation are summarized.It presented the production technology and influencing factors of the northeast suancai,examined the quality and safety issues in suancai,and put forth some ideas and opinions on the standardization development of the suancai industry.It also summarized the geographic distribution and flora diversity of pickles around the world.In order to provide some knowledge and guidance for the promotion of modern industrial production in the suancai industry.展开更多
Laser micro-nano processing technologies have been developed to address challenges that are otherwise difficult to solve in industrial applications and diverse scientific fields.These technologies offer designable pat...Laser micro-nano processing technologies have been developed to address challenges that are otherwise difficult to solve in industrial applications and diverse scientific fields.These technologies offer designable patterning,arraying capabilities,three-dimensional(3D)processing,and high precision.Recent advancements in laser technologies have demonstrated their effectiveness as powerful tools for micro-nano processing of optoelectronic materials.By utilizing various laser techniques—such as laser-induced polymerization,laser ablation,laser-induced transfer,laser-directed assembly,and laser-assisted crystallization—broad applications in image sensors,displays,solar cells,lasers,anti-counterfeiting,and information encryption have been enabled.This review comprehensively summarizes recent progress in the laser micro-nano processing of optoelectronic materials,including the technologies used for preparation,patterning,arraying,and modification.These laser fabrication methods uniquely provide capabilities such as annealing,phase transitions,and ion exchange in optoelectronic materials.We also discuss the perspectives and challenges for future developments,including the advantages,disadvantages,and potential applications of different laser micro-nano processing technologies.With the rapid advancements in laser micro-nanofabrication,we foresee significant growth in advanced,high-performance optoelectronic applications.This review aims to provide researchers with insights into the current state and future prospects of laser-based micro-nano processing,encouraging further exploration and innovation in this promising field.展开更多
基金supported by Major Science and Technology Project of Gansu Province(Grant No.23ZDGA010)National Natural Science Foundation of China(Grant No.51971105).
文摘The fabrication of 304L stainless welding wires with a diameter 1.6 mm by using electrochemical cold drawing(ECD)of bars with a diameter of 5.6 mm was investigated,as well as that via traditional cold drawing(TCD)for comparison.The results indicated that the dilute H_(2)SO_(4)aqueous solution was an appropriate electrolyte for ECD,and increasing the H_(2)SO_(4)concentration and current density within a range improved the corrosion rate and uniformity,leading to an easier and more coordinated deformation through uniformly distributing geometrically necessary dislocations and curved large-angle grain boundaries,and decreasing their density,and thus,an enhanced electrochemical plasticization(EP).Under the optimized electrochemical parameters(0.5 mol L^(-1)H_(2)SO_(4)electrolyte and current density of 12.2 mA cm^(-2)),the average cumulative reduction rate required for annealing was up to~34%,obviously higher than~20%of TCD due to the decreased work-hardening from the EP,so that the number of annealing was significantly reduced from 10 of TCD to 5,when the drawing pass was 23.In addition,the surface of the ECD wire was distinctly smoother and brighter than that of the TCD one.These findings confirm the large potential in engineering applications of the ECD technology based on the EP effect.
基金supported by National Natural Science Foundation of China(Grant No.52171032)Hebei Natural Science Foundation(Grant No.E2023501002)Fundamental Research Funds for the Central Universities(Grant No.2024GFYD003)。
文摘High entropy alloys(HEAs)have recently attracted significant attention due to their exceptional mechanical properties and potential applications across various fields.Friction stir welding and processing(FSW/P),as notable solid-state welding and processing techniques,have been proved effectiveness in enhancing microstructures and mechanical properties of HEAs.This review article summarizes the current status of FSW/P of HEAs.The welding materials and conditions used for FSW/P in HEAs are reviewed and discussed.The effects of FSW/P on the evolutions of grain structure,texture,dislocation,and secondary phase for different HEAs are highlighted.Furthermore,the influences of FSW/P on the mechanical properties of various HEAs are analyzed.Finally,potential applications,challenges,and future directions of FSW/P in HEAs are forecasted.Overall,FSW/P enable to refine grains of HEAs through dynamic recrystallization and to activate diverse deformation mechanisms of HEAs through tailoring phase structures,thereby significantly improving the strength,hardness,and ductility of both single-and dual-phase HEAs.Future progress in this field will rely on comprehensive optimization of processing parameters and alloy composition,integration of multi-scale modeling with advanced characterization for in-depth exploration of microstructural mechanisms,systematic evaluation of functional properties,and effective bridging of the gap between laboratory research and industrial application.The review aims to provide an overview of recent advancements in the FSW/P of HEAs and encourage further research in this area.
基金Project (10776020) supported by the Joint Foundation of the National Natural Science Foundation of China and China Academy of Engineering Physics
文摘In order to obtain good welding quality, it is necessary to apply quality control because there are many influencing factors in laser welding process. The key to realize welding quality control is to obtain the quality information. Abundant weld quality information is contained in weld pool and keyhole. Aiming at Nd：YAG laser welding of stainless steel, a coaxial visual sensing system was constructed. The images of weld pool and keyhole were obtained. Based on the gray character of weld pool and keyhole in images, an image processing algorithm was designed. The search start point and search criteria of weld pool and keyhole edge were determined respectively.
文摘Dissimilar AZ31B magnesium alloy and DC56D steel were welded via AA1060 aluminum alloy by magnetic pulse welding.The effects of primary and secondary welding processes on the welded interface were comparatively investigated.Macroscopic morphology,microstructure,and interfacial structure of the joints were analyzed using scanning electron microscope,energy dispersive spectrometer,and X-ray diffractometer(XRD).The results show that magnetic pulse welding of dissimilar Mg/Fe metals is achieved using an Al interlayer,which acts as a bridge for deformation and diffusion.Specifically,the AZ31B/AA1060 interface exhibits a typical wavy morphology,and a transition zone exists at the joint interface,which may result in an extremely complex microstructure.The microstructure of this transition zone differs from that of AZ31B magnesium and 1060 Al alloys,and it is identified as brittle intermetallic compounds(IMCs)Al_(3)Mg_(2) and Al_(12)Mg_(17).The transition zone is mainly distributed on the Al side,with the maximum thickness of Al-side transition layer reaching approximately 13.53μm.Incomplete melting layers with varying thicknesses are observed at the primary weld interface,while micron-sized hole defects appear in the transition zone of the secondary weld interface.The AA1060/DC56D interface is mainly straight,with only a small number of discontinuous transition zones distributed intermittently along the interface.These transition zones are characterized by the presence of the brittle IMC FeAl_(3),with a maximum thickness of about 4μm.
文摘Agricultural Products Processing and Storage(ISSN 3059-4510,Owner:Hunan Academy of Agricultural Sciences,China.Production and hosting:Springer Nature)is an international,peer-reviewed open access journal with the aim to offer a platform for the rapid dissemination of significant,novel,and high-impact research in the fields of agricultural product processing science,technology,engineering,and nutrition.Additionally,supplemental issues are curated and published to facilitate in-depth discussions on special topics.
基金funded on the one hand by Agence de l'Innovation de Défense(AID)grant reference number 2021650044on the other hand by Ecole Centrale de Nantes。
文摘Joining dissimilar materials encounters significant engineering challenges due to the contrast in material properties that makes conventional welding not feasible.Magnetic Pulse Welding(MPW)offers a solidstate joining technique that overcomes these issues by using impact to create strong bonds without melting the substrate materials.This study investigates the weldability of aluminum alloy Al-5754 with Al-7075 and MARS 380 steel,used in armouring solutions of defense systems,by the use of MPW.In this work,weldability windows are investigated by varying standoff distances between the coating material and its substrate(0.25-4.5 mm)and discharge energies(5-13 kJ)with both O-shape and U-shape inductors.Mechanical strength of the welded joints were assessed through single lap shear tests,identifying optimal welding parameters.Then,the velocity profiles of the flyer plates were measured using heterodyne velocimetry to understand the dynamics of the impact.Then,substructures assembled with the optimal welding conditions were subjected to ballistic testing using 7.62 mm×51 mm NATO and 9 mm×19 mm Parabellum munitions to evaluate the resilience of the welds under ballistic impact.The outcomes demonstrate that MPW effectively joins Al-5754 with both Al-7075 and MARS 380,producing robust welds capable of withstanding ballistic impacts under certain conditions.This research advances the application of MPW in lightweight ballistic protection of defense systems,contributing to the development of more resilient and lighter protective structures.
基金Sichuan Science and Technology Program(2025ZNSFSC1341)Fundamental Research Funds for the Central Universities(J2022-090,25CAFUC04087)。
文摘The hot compression deformation behavior of Mg-6Zn-1Mn-0.5Ca(ZM61-0.5Ca)and Mg-6Zn-1Mn-2Sn-0.5Ca(ZMT612-0.5Ca)alloys was investigated at deformation temperatures ranging from 250℃to 400℃and strain rates varying from 0.001 s^(-1) to 1 s^(-1).The results show that the addition of Sn promotes dynamic recrystallization(DRX),and CaMgSn phases can act as nucleation sites during the compression deformation.Flow stress increases with increasing the strain rate and decreasing the temperature.Both the ZM61-0.5Ca and ZMT612-0.5Ca alloys exhibit obvious DRX characteristics.CaMgSn phases can effectively inhibit dislocation motion with the addition of Sn,thus increasing the peak fl ow stress of the alloy.The addition of Sn increases the hot deformation activation energy of the ZM61-0.5Ca alloy from 199.654 kJ/mol to 276.649 kJ/mol,thus improving the thermal stability of the alloy.For the ZMT612-0.5Ca alloy,the optimal hot deformation parameters are determined to be a deformation temperature range of 350–400℃and a strain rate range of 0.001–0.01 s^(-1).
文摘Agricultural Products Processing and Storage(ISSN 3059-4510,Owner:Hunan Academy of Agricultural Sciences,China.Production and hosting:Springer Nature)is an international,peer-reviewed open access journal with the aim to offer a platform for the rapid dissemination of signifi cant,novel,and high-impact research in the fi elds of agricultural product processing science,technology,engineering,and nutrition.Additionally,supplemental issues are curated and published to facilitate in-depth discussions on special topics.
基金funded by the National Natural Science Foundation of China(Grant No.52471032).
文摘In this study,a 1400 MPa-grade ultra-high-strength steel thin-plate butt-welded joint was selected as the research object,and the joint was fabricated using the metal inert gas(MIG)welding process with ER307Si filler wire.Residual stress distributions were measured via the hole-drilling method,while micro-hardness was assessed using a micro-hardness tester.Simultaneously,both transverse shrinkage and angular distortion of the welded joint were experimentally determined.According to the hardness distribution of the joint,a thermalmetallurgical-mechanical finite element model was developed based on SYSWELD software platform.This model incorporates solid-state phase transformations(SSPT)and softening effect in the HAZ,as well as strain hardening and annealing behaviors in the weld metal.The temperature field,residual stress distribution,and welding deformation of single-pass butt-welded joint were simulated by the developed computational method.The simulation results were validated against experimental measurements,confirming the accuracy and reliability of the proposed computational approach.Furthermore,based on the numerical results,the influence mechanisms of SSPT and material softening on residual stress and deformation were analyzed.The findings indicate that SSPT exhibits considerable influences on the magnitude and distribution of welding residual stress.It reduces the peak longitudinal residual stress from 1620 MPa to 1350 MPa and increases the peak transverse residual stress from 350 MPa to 402 MPa.The results also manifest that the softening effect further reduces the peak longitudinal residual stress by 300 MPa,while exhibits minor effect on transverse residual stress.However,the results show that neither the SSPT nor the softening effect presents obvious influence on welding deformation.
基金supported by the National Natural Science Foundation of China(Grant No.52035005)the Key R&D Program of Shandong Province in China(Grant No.2021ZLGX01).
文摘The composite structures/components made by friction stir lap welding(FSLW)of Mg alloy sheet and Al alloy sheet are of wide application potentials in the manufacturing sector of transportation vehicles.To further improve the joint quality,the ultrasonic vibration(UV)is exerted in FSLW,and the UV enhanced FSLW(UVeFSLW)was developed for making Mg-to-Al dissimilar joints.The numerical analysis and experimental investigation were combined to study the process mechanism in Mg/Al UVeFSLW.An equation related to the temperature and strain rate was derived to calculate the grain size at different locations of the weld nugget zone,and the effect of grain size distribution on the threshold thermal stress was included,so that the prediction accuracy of flow stress was further improved.With such modified constitutive equation,the numerical simulation was conducted to compare the heat generation,temperature profiles and material flow behaviors in Mg/Al UVeFSLW/FSLW processes.It was found that the exerted UV decreased the temperature at two checking points on the tool/workpiece interface from 707/671 K in FSLW to 689/660 K in UVeFSLW,which suppressed the IMCs thickness at Mg-Al interface from 1.7μm in FSLW to 1.1μm in UVeFSLW.The exerted UV increased the horizontal materials flow ability,and decreased the upward flow ability,which resulted in the increase of effective sheet thickness/effective lap width from 2.01/3.70 mm in FSLW to 2.04/4.84 mm in UVeFSLW.Therefore,the ultrasonic vibration improved the tensile shear strength of Mg-to-Al lap joints by 18%.
基金supported by the National Natural Science Foundation of China(No.51804232)Beijing Municipal Natural Science Foundation(No.2212041)+1 种基金supported by the Interdisciplinary Research Project for Young Teachers of USTB(Fundamental Research Funds for the Central Universities)(FRF-IDRY-20-020)GIMRT Program of the Institute for Materials Research,Tohoku University(202303-RDKGE-0518).
文摘Low heat input welding is widely used in the industry.The microstructure and toughness of the welded joints under low heat input conditions have received less attention than those under high heat input.The impact toughness,microstructure and failure mechanisms of the coarse-grain heat-affected zone(CGHAZ)in a micro-alloyed steel were investigated by welding thermal simulation with the heat input ranging from 15 to 65 kJ/cm.The impact toughness of CGHAZ is highly sensitive to variations in low heat input.The failure mechanisms were discussed from the viewpoints of micro-voids formation and micro-cracks propagation.The micro-voids are preferred to be formed and grow at soft phase of grain boundary ferrite(GBF).At the heat inputs no more than 22 kJ/cm,martensite was dominantly formed,and the micro-cracks initiated from the GBF were propagated into the grain interiors,leading to the brittle fracture and low toughness.When the heat input was increased to 31.2 kJ/cm,granular bainite became the dominant constitute,causing cracks to deflect away from GBF and propagate into prior austenite grains.The high density high-angle and low-angle grain boundaries and the presence of retained austenite,effectively restricted the crack propagation,resulting in ductile fracture behavior and enhanced toughness.High heat input(62.3 kJ/cm)promoted coarse GBF formation,providing continuous paths for microcrack propagation.This direct intergranular crack progression caused brittle fracture and low toughness.Industrial cold cracking in the CGHAZ can thus be controlled by heat input optimization to maximize toughness.
基金supported by the Alexander von Humboldt Foundation,and Deutsche Forschungsgemeinschaft(DFG,German Research Foundation,Project No.506270597 and No.466939224).
文摘A phase-field model including magnetic field induced dendrite fragmentation was established and applied to the cases with different initial crystal nuclear positions for AA5754 aluminum alloy electromagnetic laser beam welding.Compare the calculated results that include dendrite fragmentation caused by the thermal electromagnetic Lorentz force with the results that consider only the thermal electromagnetic Lorentz force,without fragmentation,at the characteristic time instants.Both in the early and late stages,the small fragmentation at the dendrite tip promotes the number of higher-order branches and their growth,especially in the direction perpendicular to the solidification.The later stage fragmentation has the possibility of breaking one grain into several,which verifies the possibility of grain refinement caused by dendrite fragmentation.The fracture surface caused by fragmentation also makes more solid-liquid interfaces and their growth.In addition,the cases with different initial nuclear positions were compared.The grain growth in the low-temperature zone can be inhibited by the equiaxed grains'fragmentation at the high-temperature area(179.8μm^(2) and 14.7% start at the center,115.4μm^(2) and 9.4% start at the high-temperature corner,134.3μm^(2) and 10.9%start at the low-temperature corner),which is another kind of grain refinement by the dendrite fragmentation.This kind of inhibition effect on grain growth in the low-temperature region will be enhanced with the increasing time interval between the two crystal nuclei’appearance(179.8μm^(2) and 14.7%when virtual grains appear at t=4.3803 s and t=4.3803 s,134.3μm^(2) and 10.9%at t=4.0977 s and t=3.9564 s,and 115.4μm^(2) and 9.4%at t=3.8151 s and t=3.5325 s).
文摘This study investigated the effects of xu-argument-based continuation writing on learners’processing of source texts.Seventy-five participants were randomly assigned to three conditions:(1)continuation writing,(2)summary writing,or(3)reading comprehension.Eye-tracking data were collected during reading,measuring early(first fixation duration,first pass duration)and late(go-past time,total fixation duration)eye movements.During writing,source-text rereading was tracked via fixation counts and durations.Results showed that task type did not affect initial lexical access,as first fixation duration showed no group differences.However,both production groups exhibited significantly longer first pass durations than the reading comprehension group.Late measures revealed a gradient pattern:the continuation writing group spent significantly longer gopast time and total fixation duration than the summary writing group,which exceeded the reading comprehension group.This indicates that continuation tasks promoted deeper cognitive engagement during reading.During writing,the continuation writing group spent more time rereading the source text with higher fixation counts than the summary writing group.These findings suggest that continuation writing triggers more intensive reader-text interaction during pre-writing and enhances comprehension-production coupling through sustained attention to input during writing.This study sheds light on the cognitive mechanisms underlying the theoretical and pedagogical value of xu-argument.
基金supported by the Foundation of National Dairy Technology Innovation Center(2022-Open Funding Project-12)Foundation of National Dairy Technology Innovation Center(2022-Scientific Research-9)+2 种基金Key Project of National Dairy Innovation Research Center of Inner Mongolia(2021-National Dairy Innovation Research Center-8)Key Projects of Research Operating Expenses of Provincial Research Institutes in Heilongjiang Province(CZKYF2021-2-B017)Key Project of Natural Science Foundation of Heilongjiang Province(ZD2022C007).
文摘Suancai has a lengthy history and a wide range of categories,which has some influence on the pickled diet culture around the world.Suancai production is transitioning to a large-scale,standardized production due to the growth of the market.It has a unique flavor and is rich in nutrients,and its abundance of free amino acids,vitamins and phenolics has many positive effects on the human body.This review gives the types and history of suancai,as well as its impact on the world’s pickled culture.The changes in nutritional composition and flavor of suancai during fermentation are summarized.It presented the production technology and influencing factors of the northeast suancai,examined the quality and safety issues in suancai,and put forth some ideas and opinions on the standardization development of the suancai industry.It also summarized the geographic distribution and flora diversity of pickles around the world.In order to provide some knowledge and guidance for the promotion of modern industrial production in the suancai industry.
基金supported by the National Key Research and Development Program of ChinaNational Natural Science Foundation of China(NSFC)Jilin Province Science and Technology Development Plan Project under Grants 2020YFA0715000,62075081,and 20220402011GH。
文摘Laser micro-nano processing technologies have been developed to address challenges that are otherwise difficult to solve in industrial applications and diverse scientific fields.These technologies offer designable patterning,arraying capabilities,three-dimensional(3D)processing,and high precision.Recent advancements in laser technologies have demonstrated their effectiveness as powerful tools for micro-nano processing of optoelectronic materials.By utilizing various laser techniques—such as laser-induced polymerization,laser ablation,laser-induced transfer,laser-directed assembly,and laser-assisted crystallization—broad applications in image sensors,displays,solar cells,lasers,anti-counterfeiting,and information encryption have been enabled.This review comprehensively summarizes recent progress in the laser micro-nano processing of optoelectronic materials,including the technologies used for preparation,patterning,arraying,and modification.These laser fabrication methods uniquely provide capabilities such as annealing,phase transitions,and ion exchange in optoelectronic materials.We also discuss the perspectives and challenges for future developments,including the advantages,disadvantages,and potential applications of different laser micro-nano processing technologies.With the rapid advancements in laser micro-nanofabrication,we foresee significant growth in advanced,high-performance optoelectronic applications.This review aims to provide researchers with insights into the current state and future prospects of laser-based micro-nano processing,encouraging further exploration and innovation in this promising field.
