Friction stir welding was used to join two aluminum 6061-T6 plates with an insert of a pure copper plate(Al/Cu/Al),and then the influence of the copper insert on the joint performance was studied.The dissimilar weldin...Friction stir welding was used to join two aluminum 6061-T6 plates with an insert of a pure copper plate(Al/Cu/Al),and then the influence of the copper insert on the joint performance was studied.The dissimilar welding results were also compared with AA 6061 friction stir welds produced without copper insert(Al/Al).Optical and scanning electron microscopes were used for the microstructural observations of the welded samples.X-ray diffraction analysis was used to analyze phase component of the Al/Cu/Al specimen.A defect-free joint was observed for the Al/Cu/Al joint at a rotational speed of 950 r/min and a welding speed of 50 mm/min.Microstructural observation of the weld nugget zone(WNZ)demonstrates the formation of composite-like structure which promotes metallurgical bonding of aluminum and copper.XRD results show the formation of intermetallic compounds(IMCs),such as Al4Cu9 and Al2Cu.Furthermore,it was observed that the hardness of the weld with the Cu insert plate is higher than that of other samples due to more dislocation density and a distinct rise in hardness values was observed due to the presence of IMCs.The ultimate tensile strength of the joint with copper insert plate is higher than that of the other sample due to the strong metallurgical bonding between Al and Cu.展开更多
In this study,friction stir lap welding(FSLW)was performed for the welding test of 6061 aluminium alloy and T2 pure copper.The effect of process parameters containing rotation rate and travel speed on interfacial micr...In this study,friction stir lap welding(FSLW)was performed for the welding test of 6061 aluminium alloy and T2 pure copper.The effect of process parameters containing rotation rate and travel speed on interfacial microstructure evolution and mechanical properties of Al/Cu dissimilar joints were explored.The experiments were carried out under the rotation rates of 600,900 and 1200 r/min and with the travel speeds of 30,70 and 100 mm/min.The characteristic of interface transition zones(ITZs)and the species of intermetallic compounds(IMCs)were investigated.The Al/Cu interface showed a layered structure composed of Al-Cu IMCs,which will affect the mechanical property.The layer consisting of Al2Cu was formed at lower heat input,and as heat input increased the Al4Cu9 phase started to form.Excessive heat input will increase the thickness of the interface and raise the brittleness of the joints.The thickness of the IMCs layers changed from0.89μm to 3.96μm as the heat input increased.The maximum value of tensile shear loading of 4.65 kN was obtained at the rotation rate of900 r/min and travel speed of 100 mm/min with the interface thickness of 2.89μm.The fracture mode of the joints was a mix of ductile and brittle fracture.展开更多
Butt friction stir welding between pure copper and AA5754 alloy was carried out.Reinforcing SiC nanoparticles were utilized in friction stir welded(FSW)joints to decline the harmful effects of intermetallic compounds....Butt friction stir welding between pure copper and AA5754 alloy was carried out.Reinforcing SiC nanoparticles were utilized in friction stir welded(FSW)joints to decline the harmful effects of intermetallic compounds.Tensile tests,micro-hardness experiments,scanning electron microscopy and X-ray diffraction analysis were applied to studying the properties of welded joints.The joints with a travel speed of 50 mm/min and a rotation speed of 1000 r/min showed the best results.The presence of nano-sized SiC particles reduced the grain size of aluminum and copper in the stir zone(SZ)from 38.3 and 12.4μm to 12.9 and 5.1μm,respectively.The tensile strength of the joint in the presence of reinforcing SiC nano-particles was~240 MPa,which is~90%of that for the aluminum base.Furthermore,the highest microhardness of the weld zone was significantly increased from HV 160 to HV 320 upon the addition of SiC nano-particles.The results also showed that raising the heat generation in FSW joints increased the amount of Al_(4)Cu_(9) and Al_(2)Cu intermetallic compounds.展开更多
Explosive welding technique is widely used in many industries.This technique is useful to weld different kinds of metal alloys that are not easily welded by any other welding methods.Interlayer plays an important role...Explosive welding technique is widely used in many industries.This technique is useful to weld different kinds of metal alloys that are not easily welded by any other welding methods.Interlayer plays an important role to improve the welding quality and control energy loss during the collision process.In this paper,the Ti6Al4V plate was welded with a copper plate in the presence of a commercially pure titanium interlayer.Microstructure details of welded composite plate were observed through optical and scanning electron microscope.Interlayer-base plate interface morphology showed a wavy structure with solid melted regions inside the vortices.Moreover,the energy dispersive spectroscopy analysis in the interlayer-base interface reveals that there are some identified regions of different kinds of chemical equilibrium phases of CueTi,i.e.CuTi,Cu_(2)Ti,CuTi_(2),Cu_(4)Ti,etc.To study the mechanical properties of composite plates,mechanical tests were conducted,including the tensile test,bending test,shear test and Vickers hardness test.Numerical simulation of explosive welding process was performed with coupled Smooth Particle Hydrodynamic method,Euler and Arbitrary Lagrangian-Eulerian method.The multi-physics process of explosive welding,including detonation,jetting and interface morphology,was observed with simulation.Moreover,simulated plastic strain,temperature and pressure profiles were analysed to understand the welding conditions.Simulated results show that the interlayer base plate interface was created due to the high plastic deformation and localized melting of the parent plates.At the collision point,both alloys behave like fluids,resulting in the formation of a wavy morphology with vortices,which is in good agreement with the experimental results.展开更多
AA2219 Ale Cu alloy is widely used in defence and aerospace applications due to required combination of high strength-to-weight ratio and toughness.Fabrication of components used for defence always involves welding.Ev...AA2219 Ale Cu alloy is widely used in defence and aerospace applications due to required combination of high strength-to-weight ratio and toughness.Fabrication of components used for defence always involves welding.Even though the mechanical properties of the base metal are better,but the alloy suffers from poor mechanical and corrosion properties during fusion welding.To overcome the problems of fusion welding,friction stir welding(FSW) is recognized as an alternative solid state joining method aimed to improve the mechanical and corrosion properties.Tool profile is one of the important variables which affect the performance of the friction stir weld.In the present work the effect of tool profile on the microstructure and pitting corrosion of AA2219 aluminiumecopper alloy was studied.Electron backscattered diffraction results established that the grain size and orientation of weld nugget of triangle profile is finer than that of conical profile.Differential scanning calorimetric results show the evidence of precipitate dissolution during FSW.It was found that the microstructure changes,such as grain size and its orientation precipitate dissolution during FSW influence the hardness and corrosion behaviour.Pitting corrosion resistance of friction stir welds of AA2219 was found to be better for triangle profile tool compared to conical profile which is attributed to material flow and strengthening precipitate morphology in various zones.Higher amount of heat generation during FSW made using triangle profile tool may be the reason for greater dissolution of strengthening precipitates in nugget zone and coarsening in thermo mechanically affected zone(TMAZ) and heat affected zone(HAZ).展开更多
The applicatio, n of aluminum alloy in the automotive and aviation fields is impeded by the wear and life of electrode for resistance spot welding (RSW). The alloying interaction between the copper electrode and alu...The applicatio, n of aluminum alloy in the automotive and aviation fields is impeded by the wear and life of electrode for resistance spot welding (RSW). The alloying interaction between the copper electrode and aluminum alloy sheet is the main reason of making electrode life decrease. The test of alloying interaction is difficult because of the transient in RSW of aluminum alloy. In this paper, the process of alloying between copper and aluminum on the electrode tip is simulated with Gleeble-1500 thermal simulation testing machine. The microstructure and composition of the sample of physical simulation for the alloying interaction between the copper electrode and aluminum alloy are analyzed using scanning electron microscope (SEM) and X-ray diffraction (XRD) respectively. The results indicate that the alloying reaction between copper and aluminum under the different temperature, pressure and time is mainly the eutectic reaction. The reaction result is the eutectic of ( Al + CuAl2 ) , and then Cu9Al4 forms through solid diffusion between the CuAl2 phase and the copper base metal.展开更多
Cavitation erosion behavior of as-welded Cu12Mn8Al3Fe2Ni alloy in 3.5% NaCl aqueous solution was studied bymagnetostrictive vibratory device for cavitation erosion. The results show that the cavitation erosion resista...Cavitation erosion behavior of as-welded Cu12Mn8Al3Fe2Ni alloy in 3.5% NaCl aqueous solution was studied bymagnetostrictive vibratory device for cavitation erosion. The results show that the cavitation erosion resistance ofthe as-welded Cu12Mn8Al3Fe2Ni alloy is much more superior to that of the as-cast one. The cumulative mass lossand the mass loss rate of the as-welded Cu12Mn8Al3Fe2Ni alloy are almost 1/4 that of the as-cast one. SEM analysisof eroded specimens reveals that the as-cast Cu12Mn8Al3Fe2Ni alloy is attacked more severely than the as-weldedone. Microcracks causing cavitation damage initiate at the phase boundaries.展开更多
采用搅拌摩擦焊方法对2mm厚的Al Cu Li合金轧制板进行了焊接。接头内形成了焊核区、热机影响区和热影响区。焊核区由细等轴再结晶组织构成;热机影响区内的组织发生较大的弯曲变形,并在热循环的作用下发生了回复反应;热影响区形成了粗大...采用搅拌摩擦焊方法对2mm厚的Al Cu Li合金轧制板进行了焊接。接头内形成了焊核区、热机影响区和热影响区。焊核区由细等轴再结晶组织构成;热机影响区内的组织发生较大的弯曲变形,并在热循环的作用下发生了回复反应;热影响区形成了粗大的板条状组织。实验结果表明:在200mm/min的焊接速度下,接头的拉伸强度最高,达到393MPa,断裂形式为韧性和脆性的混合型断裂;在500mm/min的焊接速度下,接头强度为267.7MPa,断裂形式为脆性断裂。展开更多
为了研究Al-Cu-Mg硬铝合金TIG焊焊接接头的组织与力学性能,采用ER4043焊丝对2A12硬铝合金进行了焊接实验.利用光学显微镜、扫描电子显微镜、透射电子显微镜、能谱分析仪和硬度计对Al-Cu-Mg硬铝合金的组织和力学性能进行了表征.结果表明...为了研究Al-Cu-Mg硬铝合金TIG焊焊接接头的组织与力学性能,采用ER4043焊丝对2A12硬铝合金进行了焊接实验.利用光学显微镜、扫描电子显微镜、透射电子显微镜、能谱分析仪和硬度计对Al-Cu-Mg硬铝合金的组织和力学性能进行了表征.结果表明,焊缝的强度和塑性较低,焊缝边缘为柱状晶,中心为枝晶组织,晶界存在大量低熔点共晶体.近缝区存在明显的晶界液化现象,晶粒为圆润的等轴晶,焊缝的硬度大幅度下降.固溶区焊缝的硬度和母材相近,基体中存在大量的针状S'相,可对该区域起到强化作用.过时效区基体软化现象比较严重,存在很多S(Al2Cu M g)相.展开更多
文摘Friction stir welding was used to join two aluminum 6061-T6 plates with an insert of a pure copper plate(Al/Cu/Al),and then the influence of the copper insert on the joint performance was studied.The dissimilar welding results were also compared with AA 6061 friction stir welds produced without copper insert(Al/Al).Optical and scanning electron microscopes were used for the microstructural observations of the welded samples.X-ray diffraction analysis was used to analyze phase component of the Al/Cu/Al specimen.A defect-free joint was observed for the Al/Cu/Al joint at a rotational speed of 950 r/min and a welding speed of 50 mm/min.Microstructural observation of the weld nugget zone(WNZ)demonstrates the formation of composite-like structure which promotes metallurgical bonding of aluminum and copper.XRD results show the formation of intermetallic compounds(IMCs),such as Al4Cu9 and Al2Cu.Furthermore,it was observed that the hardness of the weld with the Cu insert plate is higher than that of other samples due to more dislocation density and a distinct rise in hardness values was observed due to the presence of IMCs.The ultimate tensile strength of the joint with copper insert plate is higher than that of the other sample due to the strong metallurgical bonding between Al and Cu.
基金supported by the Key project of Education Department of Hebei Province(Grant No.ZD2019102)。
文摘In this study,friction stir lap welding(FSLW)was performed for the welding test of 6061 aluminium alloy and T2 pure copper.The effect of process parameters containing rotation rate and travel speed on interfacial microstructure evolution and mechanical properties of Al/Cu dissimilar joints were explored.The experiments were carried out under the rotation rates of 600,900 and 1200 r/min and with the travel speeds of 30,70 and 100 mm/min.The characteristic of interface transition zones(ITZs)and the species of intermetallic compounds(IMCs)were investigated.The Al/Cu interface showed a layered structure composed of Al-Cu IMCs,which will affect the mechanical property.The layer consisting of Al2Cu was formed at lower heat input,and as heat input increased the Al4Cu9 phase started to form.Excessive heat input will increase the thickness of the interface and raise the brittleness of the joints.The thickness of the IMCs layers changed from0.89μm to 3.96μm as the heat input increased.The maximum value of tensile shear loading of 4.65 kN was obtained at the rotation rate of900 r/min and travel speed of 100 mm/min with the interface thickness of 2.89μm.The fracture mode of the joints was a mix of ductile and brittle fracture.
文摘Butt friction stir welding between pure copper and AA5754 alloy was carried out.Reinforcing SiC nanoparticles were utilized in friction stir welded(FSW)joints to decline the harmful effects of intermetallic compounds.Tensile tests,micro-hardness experiments,scanning electron microscopy and X-ray diffraction analysis were applied to studying the properties of welded joints.The joints with a travel speed of 50 mm/min and a rotation speed of 1000 r/min showed the best results.The presence of nano-sized SiC particles reduced the grain size of aluminum and copper in the stir zone(SZ)from 38.3 and 12.4μm to 12.9 and 5.1μm,respectively.The tensile strength of the joint in the presence of reinforcing SiC nano-particles was~240 MPa,which is~90%of that for the aluminum base.Furthermore,the highest microhardness of the weld zone was significantly increased from HV 160 to HV 320 upon the addition of SiC nano-particles.The results also showed that raising the heat generation in FSW joints increased the amount of Al_(4)Cu_(9) and Al_(2)Cu intermetallic compounds.
文摘Explosive welding technique is widely used in many industries.This technique is useful to weld different kinds of metal alloys that are not easily welded by any other welding methods.Interlayer plays an important role to improve the welding quality and control energy loss during the collision process.In this paper,the Ti6Al4V plate was welded with a copper plate in the presence of a commercially pure titanium interlayer.Microstructure details of welded composite plate were observed through optical and scanning electron microscope.Interlayer-base plate interface morphology showed a wavy structure with solid melted regions inside the vortices.Moreover,the energy dispersive spectroscopy analysis in the interlayer-base interface reveals that there are some identified regions of different kinds of chemical equilibrium phases of CueTi,i.e.CuTi,Cu_(2)Ti,CuTi_(2),Cu_(4)Ti,etc.To study the mechanical properties of composite plates,mechanical tests were conducted,including the tensile test,bending test,shear test and Vickers hardness test.Numerical simulation of explosive welding process was performed with coupled Smooth Particle Hydrodynamic method,Euler and Arbitrary Lagrangian-Eulerian method.The multi-physics process of explosive welding,including detonation,jetting and interface morphology,was observed with simulation.Moreover,simulated plastic strain,temperature and pressure profiles were analysed to understand the welding conditions.Simulated results show that the interlayer base plate interface was created due to the high plastic deformation and localized melting of the parent plates.At the collision point,both alloys behave like fluids,resulting in the formation of a wavy morphology with vortices,which is in good agreement with the experimental results.
文摘AA2219 Ale Cu alloy is widely used in defence and aerospace applications due to required combination of high strength-to-weight ratio and toughness.Fabrication of components used for defence always involves welding.Even though the mechanical properties of the base metal are better,but the alloy suffers from poor mechanical and corrosion properties during fusion welding.To overcome the problems of fusion welding,friction stir welding(FSW) is recognized as an alternative solid state joining method aimed to improve the mechanical and corrosion properties.Tool profile is one of the important variables which affect the performance of the friction stir weld.In the present work the effect of tool profile on the microstructure and pitting corrosion of AA2219 aluminiumecopper alloy was studied.Electron backscattered diffraction results established that the grain size and orientation of weld nugget of triangle profile is finer than that of conical profile.Differential scanning calorimetric results show the evidence of precipitate dissolution during FSW.It was found that the microstructure changes,such as grain size and its orientation precipitate dissolution during FSW influence the hardness and corrosion behaviour.Pitting corrosion resistance of friction stir welds of AA2219 was found to be better for triangle profile tool compared to conical profile which is attributed to material flow and strengthening precipitate morphology in various zones.Higher amount of heat generation during FSW made using triangle profile tool may be the reason for greater dissolution of strengthening precipitates in nugget zone and coarsening in thermo mechanically affected zone(TMAZ) and heat affected zone(HAZ).
基金This project was supported by Provincial Natural Science Foundation of Shanxi (No. 2009011028-2) , Provincial Outstanding Graduate Innovation Projection of Shanxi (No. 20103093 ) and Star Special Projection of Taiyuan (No. 09121013).
文摘The applicatio, n of aluminum alloy in the automotive and aviation fields is impeded by the wear and life of electrode for resistance spot welding (RSW). The alloying interaction between the copper electrode and aluminum alloy sheet is the main reason of making electrode life decrease. The test of alloying interaction is difficult because of the transient in RSW of aluminum alloy. In this paper, the process of alloying between copper and aluminum on the electrode tip is simulated with Gleeble-1500 thermal simulation testing machine. The microstructure and composition of the sample of physical simulation for the alloying interaction between the copper electrode and aluminum alloy are analyzed using scanning electron microscope (SEM) and X-ray diffraction (XRD) respectively. The results indicate that the alloying reaction between copper and aluminum under the different temperature, pressure and time is mainly the eutectic reaction. The reaction result is the eutectic of ( Al + CuAl2 ) , and then Cu9Al4 forms through solid diffusion between the CuAl2 phase and the copper base metal.
文摘Cavitation erosion behavior of as-welded Cu12Mn8Al3Fe2Ni alloy in 3.5% NaCl aqueous solution was studied bymagnetostrictive vibratory device for cavitation erosion. The results show that the cavitation erosion resistance ofthe as-welded Cu12Mn8Al3Fe2Ni alloy is much more superior to that of the as-cast one. The cumulative mass lossand the mass loss rate of the as-welded Cu12Mn8Al3Fe2Ni alloy are almost 1/4 that of the as-cast one. SEM analysisof eroded specimens reveals that the as-cast Cu12Mn8Al3Fe2Ni alloy is attacked more severely than the as-weldedone. Microcracks causing cavitation damage initiate at the phase boundaries.
文摘采用搅拌摩擦焊方法对2mm厚的Al Cu Li合金轧制板进行了焊接。接头内形成了焊核区、热机影响区和热影响区。焊核区由细等轴再结晶组织构成;热机影响区内的组织发生较大的弯曲变形,并在热循环的作用下发生了回复反应;热影响区形成了粗大的板条状组织。实验结果表明:在200mm/min的焊接速度下,接头的拉伸强度最高,达到393MPa,断裂形式为韧性和脆性的混合型断裂;在500mm/min的焊接速度下,接头强度为267.7MPa,断裂形式为脆性断裂。
文摘为了研究Al-Cu-Mg硬铝合金TIG焊焊接接头的组织与力学性能,采用ER4043焊丝对2A12硬铝合金进行了焊接实验.利用光学显微镜、扫描电子显微镜、透射电子显微镜、能谱分析仪和硬度计对Al-Cu-Mg硬铝合金的组织和力学性能进行了表征.结果表明,焊缝的强度和塑性较低,焊缝边缘为柱状晶,中心为枝晶组织,晶界存在大量低熔点共晶体.近缝区存在明显的晶界液化现象,晶粒为圆润的等轴晶,焊缝的硬度大幅度下降.固溶区焊缝的硬度和母材相近,基体中存在大量的针状S'相,可对该区域起到强化作用.过时效区基体软化现象比较严重,存在很多S(Al2Cu M g)相.