A new method was proposed for preparing AZ31/1060 composite plates with a corrugated interface,which involved cold-pressing a corrugated surface on the Al plate and then hot-pressing the assembled Mg/Al plate.The resu...A new method was proposed for preparing AZ31/1060 composite plates with a corrugated interface,which involved cold-pressing a corrugated surface on the Al plate and then hot-pressing the assembled Mg/Al plate.The results show that cold-pressing produces intense plastic deformation near the corrugated surface of the Al plate,which promotes dynamic recrystallization of the Al substrate near the interface during the subsequent hot-pressing.In addition,the initial corrugation on the surface of the Al plate also changes the local stress state near the interface during hot pressing,which has a large effect on the texture components of the substrates near the corrugated interface.The construction of the corrugated interface can greatly enhance the shear strength by 2−4 times due to the increased contact area and the strong“mechanical gearing”effect.Moreover,the mechanical properties are largely depended on the orientation relationship between corrugated direction and loading direction.展开更多
Titanium plates with a Ti−O solid solution surface-hardened layer were cold roll-bonded with 304 stainless steel plates with high work hardening rates.The evolution and mechanisms affecting the interfacial bonding str...Titanium plates with a Ti−O solid solution surface-hardened layer were cold roll-bonded with 304 stainless steel plates with high work hardening rates.The evolution and mechanisms affecting the interfacial bonding strength in titanium/stainless steel laminated composites were investigated.Results indicate that the hardened layer reduces the interfacial bonding strength from over 261 MPa to less than 204 MPa.During the cold roll-bonding process,the hardened layer fractures,leading to the formation of multi-scale cracks that are difficult for the stainless steel to fill.This not only hinders the development of an interlocking interface but also leads to the presence of numerous microcracks and hardened blocks along the nearly straight interface,consequently weakening the interfacial bonding strength.In metals with high work hardening rates,the conventional approach of enhancing interface interlocking and improving interfacial bonding strength by using a surface-hardened layer becomes less effective.展开更多
Lap joints of TC1 Ti alloy and LF6 A1 alloy dissimilar materials were fabricated by friction stir welding and corresponding interface characteristics were investigated. Using the selected welding parameters, excellent...Lap joints of TC1 Ti alloy and LF6 A1 alloy dissimilar materials were fabricated by friction stir welding and corresponding interface characteristics were investigated. Using the selected welding parameters, excellent surface appearance forms, but the interface macrograph for each lap joint cross-section is different. With the increase of welding speed or the decrease of tool rotation rate, the amount of Ti alloy particles stirred into the stir zone by the force of tool pin decreases continuously. Moreover, the failure loads of the lap joints also decrease with increasing welding speed and the largest value is achieved at welding speed of 60 mm/min and tool rotation rate of 1500 r/min, where the interracial zone can be divided into 3 kinds of layers. The microhardness of the lap joint shows an uneven distribution and the maximum hardness of HV 502 is found in the middle of the stir zone.展开更多
35% SiCp/2024 Al（volume fraction） composite was prepared by powder metallurgy method. The microstructures of Si Cp/Al interfaces and precipitate phase/Al interfaces were characterized by HRTEM, and the interface con...35% SiCp/2024 Al（volume fraction） composite was prepared by powder metallurgy method. The microstructures of Si Cp/Al interfaces and precipitate phase/Al interfaces were characterized by HRTEM, and the interface conditions were evaluated by tensile modules of elasticity and Brinell hardness measurement. The results show that the overall Si Cp/Al interface condition in this experiment is good and three kinds of Si Cp/Al interfaces are present in the composites, which include vast majority of clean planer interfaces, few slight reaction interfaces and tiny amorphous interfaces. The combination mechanism of Si C and Al in the clean planer interface is the formation of a semi-coherent interface by closely matching of atoms and there are no fixed or preferential crystallographic orientation relationships between Si C and Al. MgAl2O4 spinel particles act as an intermediate to form semi-coherent interface with SiC and Al respectively at the slight reaction interfaces. When the composite is aged at 190 °C for 9 h after being solution-treated at 510 °C for 2 h, numerous discoid-shaped and needle-shaped nanosized precipitates dispersively exist in the composite and are semi-coherent of low mismatch with Al matrix. The Brinell hardness of composites arrives peak value at this time.展开更多
A Fe/Al clad tube was prepared by explosive welding.Then the bonding characteristic of the interface was investigated by compression,flattening and compression-shear test.The test results exhibit that the clad tubes p...A Fe/Al clad tube was prepared by explosive welding.Then the bonding characteristic of the interface was investigated by compression,flattening and compression-shear test.The test results exhibit that the clad tubes possessing good bonding interface have higher shear strength than that of pure aluminum and can bear both axial and radial deformation.The original interface between aluminum layer and ferrite layer was observed by scanning electron microscopy（SEM）.The results show that the clad tubes with good bonding properties possess the interface in wave and straight shape.The Fe/Al clad tube was used to manufacture the T-shape by hydro-bulging.It is found that the good-bonding interface of the Fe/Al clad tube plays a dominant role in the formation of the T-shape.展开更多
A nickel-based coating was deposited on the pure Al substrate by immersion plating,and the Al/Cu bimetals were prepared by diffusion bonding in the temperature range of 450-550 ℃.The interce microstructure and fractu...A nickel-based coating was deposited on the pure Al substrate by immersion plating,and the Al/Cu bimetals were prepared by diffusion bonding in the temperature range of 450-550 ℃.The interce microstructure and fracture surface of Al/Cu joints were studied by scanning electron microscopy（SEM） and X-ray diffraction（XRD）.The mechanical properties of the Al/Cu bimetals were measured by tensile shear and microhardness tests.The results show that the Ni interiayer can effectively eliminate the formation of Al-Cu intermetallic compounds.The Al/Ni interface consists of the Al3Ni and Al3Ni2 phases,while it is Ni-Cu solid solution at the Ni/Cu interce.The tensile shear strength of the joints is improved by the addition of Ni interiayer.The joint with Ni interiayer annealed at 500 ℃ exhibits a maximum value of tensile shear strength of 34.7 MPa.展开更多
Al-Ti diffusion couples were made by embedded technology and treated at the temperature between the melting points of Al and Ti. The microstructure evolution and growth mechanism of the Al-Ti DRZ were investigated. Th...Al-Ti diffusion couples were made by embedded technology and treated at the temperature between the melting points of Al and Ti. The microstructure evolution and growth mechanism of the Al-Ti DRZ were investigated. The result shows that the DRZ, the mixture of TiAl3 and Al, grows layer by layer along their chemical equilibrium zone. In the course, the growth interface moves toward the aluminum side. TiAl3 is the only new phase which forms earliest in the course of heat-treatment. The growth mechanism of the DRZ changes after the phase transition of titanium. Before the phase transition of titanium, the growth of the DRZ is controlled by the dissolution speed of the titanium to the molten aluminum, while after the phase transition of titanium, the growth is controlled by the chemical reaction speed of Al and Ti atoms, and consequently, its growth rate is greatly increased.展开更多
Welding deformation adversely affects the quality and precision of structural components,and traditional methods require significant material resources and time.Machine learning has demonstrated exceptional ac-curacy ...Welding deformation adversely affects the quality and precision of structural components,and traditional methods require significant material resources and time.Machine learning has demonstrated exceptional ac-curacy and efficiency in solving complex problems.Thus,the use of machine learning to predict welding de-formations is a novel approach.In this study,laser welding experiments were conducted on a TC4 titanium alloy to establish a welding deformation dataset.The deep neural network(DNN)and convolutional neural network(CNN)models were designed and constructed,with average prediction errors of 0.85 mm and 0.94 mm on the validation set,respectively.To further optimize the network parameters,a differential evolution algorithm was employed through mutation,crossover,and selection.The results indicated that after optimization,the pre-diction errors of the DNN and CNN models reduced to 0.75 mm and 0.85 mm,respectively.These represent accuracy improvements of 14.8%and 9.6%,respectively.The optimized models exhibited superior predictive performances for the validation set.展开更多
Fabricating Mg/Al laminate is an effective strategy to circumvent the inherently low formability and poor corrosion resistance of Mg alloys.Here,Mg/Al laminate with good bonding quality and mechanical properties was s...Fabricating Mg/Al laminate is an effective strategy to circumvent the inherently low formability and poor corrosion resistance of Mg alloys.Here,Mg/Al laminate with good bonding quality and mechanical properties was successfully fabricated via porthole die co-extrusion process using ZK60 Mg and TiB_(2)/6061Al composite as constituted layers.Integrating the results from microstructural characterization and mechanical testing,the effects of extrusion temperature on microstructure,interfacial structure,element diffusion,and mechanical properties were investigated.The results show that Mg/Al laminate achieves a sound welding quality by mechanical bonding and diffusion bonding.The obvious intermetallic compounds(βandγ)layer forms at Mg/Al interface,and its thickness increases to 8.3μm as the extrusion temperature reaches 400℃.High extrusion temperature promotes the dynamic recrystallization and grain growth of Mg and Al layers,while the dislocation density decreases.β/γinterface shows a coherent feature,whileγ/Mg interface is semi-coherent with a locally ordered transition zone of 4.5 nm.The rich Mg and Cr layers are found at TiB_(2)/6061 interface,which is conducive to improving the bonding quality.When the extrusion temperature is 370℃,the thickness of diffusion layer is around 5.0μm,and the bonding strength reaches 18.68 MPa,resulting in the best comprehensive mechanical properties.This work provides a new direction for the development of Mg/Al laminate with excellent strength and ductility.展开更多
基金supported by Guangdong Major Project of Basic and Applied Basic Research, China (No. 2020B0301030006)Fundamental Research Funds for the Central Universities, China (No. SWU-XDJH202313)+1 种基金Chongqing Postdoctoral Science Foundation Funded Project, China (No. 2112012728014435)the Chongqing Postgraduate Research and Innovation Project, China (No. CYS23197)。
文摘A new method was proposed for preparing AZ31/1060 composite plates with a corrugated interface,which involved cold-pressing a corrugated surface on the Al plate and then hot-pressing the assembled Mg/Al plate.The results show that cold-pressing produces intense plastic deformation near the corrugated surface of the Al plate,which promotes dynamic recrystallization of the Al substrate near the interface during the subsequent hot-pressing.In addition,the initial corrugation on the surface of the Al plate also changes the local stress state near the interface during hot pressing,which has a large effect on the texture components of the substrates near the corrugated interface.The construction of the corrugated interface can greatly enhance the shear strength by 2−4 times due to the increased contact area and the strong“mechanical gearing”effect.Moreover,the mechanical properties are largely depended on the orientation relationship between corrugated direction and loading direction.
基金supported by the National Key R&D Program of China (No. 2018YFA0707300)the National Natural Science Foundation of China (No. 52374376)the Introduction Plan for High end Foreign Experts, China (No. G2023105001L)。
文摘Titanium plates with a Ti−O solid solution surface-hardened layer were cold roll-bonded with 304 stainless steel plates with high work hardening rates.The evolution and mechanisms affecting the interfacial bonding strength in titanium/stainless steel laminated composites were investigated.Results indicate that the hardened layer reduces the interfacial bonding strength from over 261 MPa to less than 204 MPa.During the cold roll-bonding process,the hardened layer fractures,leading to the formation of multi-scale cracks that are difficult for the stainless steel to fill.This not only hinders the development of an interlocking interface but also leads to the presence of numerous microcracks and hardened blocks along the nearly straight interface,consequently weakening the interfacial bonding strength.In metals with high work hardening rates,the conventional approach of enhancing interface interlocking and improving interfacial bonding strength by using a surface-hardened layer becomes less effective.
基金Project (2011BAB206006) supported by the Natural Science Foundation of Jiangxi Province,ChinaProject (2009ZE56011) supported by the Aviation Science Funds of ChinaProject (GJJ12411) supported by the Education Department of Jiangxi Province,China
文摘Lap joints of TC1 Ti alloy and LF6 A1 alloy dissimilar materials were fabricated by friction stir welding and corresponding interface characteristics were investigated. Using the selected welding parameters, excellent surface appearance forms, but the interface macrograph for each lap joint cross-section is different. With the increase of welding speed or the decrease of tool rotation rate, the amount of Ti alloy particles stirred into the stir zone by the force of tool pin decreases continuously. Moreover, the failure loads of the lap joints also decrease with increasing welding speed and the largest value is achieved at welding speed of 60 mm/min and tool rotation rate of 1500 r/min, where the interracial zone can be divided into 3 kinds of layers. The microhardness of the lap joint shows an uneven distribution and the maximum hardness of HV 502 is found in the middle of the stir zone.
基金Project(51371077)supported by the National Natural Science Foundation of China
文摘35% SiCp/2024 Al（volume fraction） composite was prepared by powder metallurgy method. The microstructures of Si Cp/Al interfaces and precipitate phase/Al interfaces were characterized by HRTEM, and the interface conditions were evaluated by tensile modules of elasticity and Brinell hardness measurement. The results show that the overall Si Cp/Al interface condition in this experiment is good and three kinds of Si Cp/Al interfaces are present in the composites, which include vast majority of clean planer interfaces, few slight reaction interfaces and tiny amorphous interfaces. The combination mechanism of Si C and Al in the clean planer interface is the formation of a semi-coherent interface by closely matching of atoms and there are no fixed or preferential crystallographic orientation relationships between Si C and Al. MgAl2O4 spinel particles act as an intermediate to form semi-coherent interface with SiC and Al respectively at the slight reaction interfaces. When the composite is aged at 190 °C for 9 h after being solution-treated at 510 °C for 2 h, numerous discoid-shaped and needle-shaped nanosized precipitates dispersively exist in the composite and are semi-coherent of low mismatch with Al matrix. The Brinell hardness of composites arrives peak value at this time.
基金Project(BA2006067)supported by Achievement Transitional Foundation of Jiangsu Province,China
文摘A Fe/Al clad tube was prepared by explosive welding.Then the bonding characteristic of the interface was investigated by compression,flattening and compression-shear test.The test results exhibit that the clad tubes possessing good bonding interface have higher shear strength than that of pure aluminum and can bear both axial and radial deformation.The original interface between aluminum layer and ferrite layer was observed by scanning electron microscopy（SEM）.The results show that the clad tubes with good bonding properties possess the interface in wave and straight shape.The Fe/Al clad tube was used to manufacture the T-shape by hydro-bulging.It is found that the good-bonding interface of the Fe/Al clad tube plays a dominant role in the formation of the T-shape.
基金Projects (51274054,51375070,51271042) supported by the National Natural Science Foundation of ChinaProjects (2013M530913) supported by the China Postdoctoral Science Foundation
文摘A nickel-based coating was deposited on the pure Al substrate by immersion plating,and the Al/Cu bimetals were prepared by diffusion bonding in the temperature range of 450-550 ℃.The interce microstructure and fracture surface of Al/Cu joints were studied by scanning electron microscopy（SEM） and X-ray diffraction（XRD）.The mechanical properties of the Al/Cu bimetals were measured by tensile shear and microhardness tests.The results show that the Ni interiayer can effectively eliminate the formation of Al-Cu intermetallic compounds.The Al/Ni interface consists of the Al3Ni and Al3Ni2 phases,while it is Ni-Cu solid solution at the Ni/Cu interce.The tensile shear strength of the joints is improved by the addition of Ni interiayer.The joint with Ni interiayer annealed at 500 ℃ exhibits a maximum value of tensile shear strength of 34.7 MPa.
基金Project (ZR2011EL023) supported by the Natural Science Foundation of Shandong Province,ChinaProject (12CX04057A) supported by the Fundamental Research Funds for the Central Universities,China
文摘Al-Ti diffusion couples were made by embedded technology and treated at the temperature between the melting points of Al and Ti. The microstructure evolution and growth mechanism of the Al-Ti DRZ were investigated. The result shows that the DRZ, the mixture of TiAl3 and Al, grows layer by layer along their chemical equilibrium zone. In the course, the growth interface moves toward the aluminum side. TiAl3 is the only new phase which forms earliest in the course of heat-treatment. The growth mechanism of the DRZ changes after the phase transition of titanium. Before the phase transition of titanium, the growth of the DRZ is controlled by the dissolution speed of the titanium to the molten aluminum, while after the phase transition of titanium, the growth is controlled by the chemical reaction speed of Al and Ti atoms, and consequently, its growth rate is greatly increased.
基金Supported by Defense Industrial Technology Development Program of China(Grant No.JCKY2021605B015).
文摘Welding deformation adversely affects the quality and precision of structural components,and traditional methods require significant material resources and time.Machine learning has demonstrated exceptional ac-curacy and efficiency in solving complex problems.Thus,the use of machine learning to predict welding de-formations is a novel approach.In this study,laser welding experiments were conducted on a TC4 titanium alloy to establish a welding deformation dataset.The deep neural network(DNN)and convolutional neural network(CNN)models were designed and constructed,with average prediction errors of 0.85 mm and 0.94 mm on the validation set,respectively.To further optimize the network parameters,a differential evolution algorithm was employed through mutation,crossover,and selection.The results indicated that after optimization,the pre-diction errors of the DNN and CNN models reduced to 0.75 mm and 0.85 mm,respectively.These represent accuracy improvements of 14.8%and 9.6%,respectively.The optimized models exhibited superior predictive performances for the validation set.
基金supports from the National Natural Science Foundation of China(52175338 and 52222510)Science Fund for Distinguished Young Scholars of Shandong Province(ZR2021JQ21)Key Research and Development Program of Shandong Province(2021ZLGX01).
文摘Fabricating Mg/Al laminate is an effective strategy to circumvent the inherently low formability and poor corrosion resistance of Mg alloys.Here,Mg/Al laminate with good bonding quality and mechanical properties was successfully fabricated via porthole die co-extrusion process using ZK60 Mg and TiB_(2)/6061Al composite as constituted layers.Integrating the results from microstructural characterization and mechanical testing,the effects of extrusion temperature on microstructure,interfacial structure,element diffusion,and mechanical properties were investigated.The results show that Mg/Al laminate achieves a sound welding quality by mechanical bonding and diffusion bonding.The obvious intermetallic compounds(βandγ)layer forms at Mg/Al interface,and its thickness increases to 8.3μm as the extrusion temperature reaches 400℃.High extrusion temperature promotes the dynamic recrystallization and grain growth of Mg and Al layers,while the dislocation density decreases.β/γinterface shows a coherent feature,whileγ/Mg interface is semi-coherent with a locally ordered transition zone of 4.5 nm.The rich Mg and Cr layers are found at TiB_(2)/6061 interface,which is conducive to improving the bonding quality.When the extrusion temperature is 370℃,the thickness of diffusion layer is around 5.0μm,and the bonding strength reaches 18.68 MPa,resulting in the best comprehensive mechanical properties.This work provides a new direction for the development of Mg/Al laminate with excellent strength and ductility.
