According to the differences in melting point between aluminum alloy and steel, 6013-T4 aluminum alloy was joined to galvanized steel by large spot Nd：YAG laser ＋ MIG arc hybrid brazing-fusion welding with ER4043（A...According to the differences in melting point between aluminum alloy and steel, 6013-T4 aluminum alloy was joined to galvanized steel by large spot Nd：YAG laser ＋ MIG arc hybrid brazing-fusion welding with ER4043（AlSi5） filler wire. The microstructures and mechanical properties of the brazed-fusion welded joint were investigated. The joint is divided into two parts of fusion weld and brazed seam. There is a zinc-rich zone at fusion weld toe, which consists of α（Al）-Zn solid solution and Al-Zn eutectic. The brazed seam is the Fe-Al intermetallic compounds （IMCs） layer of 2-4μm in thickness, and the IMCs include FeAl2, Fe2Al5 and Fe4Al13. FeAl2 and Fe2Al5 are located in the compact reaction layer near the steel side, and Fe4Al13 with tongue shape or sawtooth shape grows towards the fusion weld. The tensile strength of the joint firstly increases and then decreases as the welding current and laser power increase, the highest tensile strength can be up to 247.3 MPa, and the fracture usually occurs at fusion zone of the fusion weld. The hardness is the highest at the brazed seam because of hard Fe-Al IMCs, and gradually decreases along the fusion weld and galvanized steel, respectively.展开更多
The effects of rapid solidification on the microstructure and melting behavior of the Sn-8Zn-3Bi alloy were studied. The evolution of the microstructuraI characteristics of the solder/Cu joint after an isothermal agin...The effects of rapid solidification on the microstructure and melting behavior of the Sn-8Zn-3Bi alloy were studied. The evolution of the microstructuraI characteristics of the solder/Cu joint after an isothermal aging at 150 ℃ was also analyzed to evaluate the interconnect reliability. Results showed that the Bi in Sn-8Zn-3Bi solder alloy completely dissolved in the Sn matrix with a dendritic structure after rapid solidification. Compared with as-solidified Sn-8Zn-3Bi solder alloy, the melting temperature of the rapid solidified alloy rose to close to that of the Sn-Zn eutectic alloy due to the extreme dissolution of Bi in Sn matrix. Meanwhile, the adverse effect on melting behavior due to Bi addition was decreased significantly. The interfacial intermetallic compound （IMC） layer of the solder/Cu joint was more compact and uniform. Rapid solidification process obviously depressed the formation and growth of the interfacial IMC during the high-temperature aging and improved the high-temperature stability of the Sn-8Zn-3Bi solder/Cu joint.展开更多
The thermo-elastic.plastic finite element method(FEM)is used to simulate the thermo-mechanical behavior of Al/steel tungsten inert gas(TIG)arc-assisted laser welding-brazing(A-LWB)butt joint.The influence of material ...The thermo-elastic.plastic finite element method(FEM)is used to simulate the thermo-mechanical behavior of Al/steel tungsten inert gas(TIG)arc-assisted laser welding-brazing(A-LWB)butt joint.The influence of material nonlinearity,geometrical nonlinearity and work hardening on the welding process is studied,and the differences in the welding temperature field,residual stress and welding distortion by A-LWB and by single laser welding-brazing(SLWB)are analyzed.The results show that the thermal cycle,residual stress distribution and welding distortion by the numerical simulation are in good agreement with the measured data by experiments,which verifies the effectiveness of FEM.Compared with the SLWB,A-LWB can make the high-temperature distribution zone of weld in width direction wider,decrease the transverse tensile stress in the weld and reduce the distribution range of longitudinal tensile stress.And the welding deformation also decreases to some extent.展开更多
A new hybrid welding process was successfully used to join aluminum alloy and stainless steel. In the MIG welding-brazing process, the lower thermal conductivity of steel can cause dramatic change of temperature gradi...A new hybrid welding process was successfully used to join aluminum alloy and stainless steel. In the MIG welding-brazing process, the lower thermal conductivity of steel can cause dramatic change of temperature gradient on steel surface, while the auxiliary TIG arc can change this phenomenon by heating the steel side. The auxiliary TIG improved the wettability of molten metal, resulting in the molten metal spreading fully on upper surfaces, front and back surface of steel, forming a sound brazing joint; the content of Cr and Ni elements in IMCs layer was increased, which can enhance the quality of the layer; and the microstructure of IMCs layer also was improved, increasing the bonding strength with the weld seam. The average tensile strength of the joint obtained with auxiliary TIG arc（146.7 MPa） was higher than that without auxiliary TIG arc（96.7 MPa）.展开更多
Laser-metal inert-gas(MIG)hybrid welding-brazing was applied to the butt joint of 6061-T6 aluminum alloy and 304 stainless steel.The microstructure and mechanical properties of the joint were studied.An excellent join...Laser-metal inert-gas(MIG)hybrid welding-brazing was applied to the butt joint of 6061-T6 aluminum alloy and 304 stainless steel.The microstructure and mechanical properties of the joint were studied.An excellent joint-section shape was achieved from good wettability on both sides of the stainless steel.Scanning electron microscopy,energy-dispersive spectroscopy and X-ray diffractometry indicated an intermetallic compound(IMC)layer at the 6061-T6/304 interface.The IMC thickness was controlled to be^2μm,which was attributed to the advantage of the laser-MIG hybrid method.Fe3Al dominated in the IMC layer at the interface between the stainless steel and the back reinforcement.The IMC layer in the remaining regions consisted mainly of Fe4Al13.A thinner IMC layer and better wettability on both sides of the stainless steel were obtained,because of the optimized energy distribution from a combination of a laser beam with a MIG arc.The average tensile strength of the joint with reinforcement using laser-MIG hybrid process was improved to be 174 MPa(60%of the 6061-T6 tensile strength),which was significantly higher than that of the joint by traditional MIG process.展开更多
基金Project (50905099) supported by the National Natural Science Foundation of ChinaProject (20090131120027) supported by the Specialized Research Fund for the Doctoral Program of Higher Education,China
文摘According to the differences in melting point between aluminum alloy and steel, 6013-T4 aluminum alloy was joined to galvanized steel by large spot Nd：YAG laser ＋ MIG arc hybrid brazing-fusion welding with ER4043（AlSi5） filler wire. The microstructures and mechanical properties of the brazed-fusion welded joint were investigated. The joint is divided into two parts of fusion weld and brazed seam. There is a zinc-rich zone at fusion weld toe, which consists of α（Al）-Zn solid solution and Al-Zn eutectic. The brazed seam is the Fe-Al intermetallic compounds （IMCs） layer of 2-4μm in thickness, and the IMCs include FeAl2, Fe2Al5 and Fe4Al13. FeAl2 and Fe2Al5 are located in the compact reaction layer near the steel side, and Fe4Al13 with tongue shape or sawtooth shape grows towards the fusion weld. The tensile strength of the joint firstly increases and then decreases as the welding current and laser power increase, the highest tensile strength can be up to 247.3 MPa, and the fracture usually occurs at fusion zone of the fusion weld. The hardness is the highest at the brazed seam because of hard Fe-Al IMCs, and gradually decreases along the fusion weld and galvanized steel, respectively.
基金Project(50675234)supported by the National Natural Science Foundation of China
文摘The effects of rapid solidification on the microstructure and melting behavior of the Sn-8Zn-3Bi alloy were studied. The evolution of the microstructuraI characteristics of the solder/Cu joint after an isothermal aging at 150 ℃ was also analyzed to evaluate the interconnect reliability. Results showed that the Bi in Sn-8Zn-3Bi solder alloy completely dissolved in the Sn matrix with a dendritic structure after rapid solidification. Compared with as-solidified Sn-8Zn-3Bi solder alloy, the melting temperature of the rapid solidified alloy rose to close to that of the Sn-Zn eutectic alloy due to the extreme dissolution of Bi in Sn matrix. Meanwhile, the adverse effect on melting behavior due to Bi addition was decreased significantly. The interfacial intermetallic compound （IMC） layer of the solder/Cu joint was more compact and uniform. Rapid solidification process obviously depressed the formation and growth of the interfacial IMC during the high-temperature aging and improved the high-temperature stability of the Sn-8Zn-3Bi solder/Cu joint.
基金Project(51465031)supported by the National Natural Science Foundation of ChinaProject(17JR5RA126)supported by the Natural Science Foundation of Gansu Province,China
文摘The thermo-elastic.plastic finite element method(FEM)is used to simulate the thermo-mechanical behavior of Al/steel tungsten inert gas(TIG)arc-assisted laser welding-brazing(A-LWB)butt joint.The influence of material nonlinearity,geometrical nonlinearity and work hardening on the welding process is studied,and the differences in the welding temperature field,residual stress and welding distortion by A-LWB and by single laser welding-brazing(SLWB)are analyzed.The results show that the thermal cycle,residual stress distribution and welding distortion by the numerical simulation are in good agreement with the measured data by experiments,which verifies the effectiveness of FEM.Compared with the SLWB,A-LWB can make the high-temperature distribution zone of weld in width direction wider,decrease the transverse tensile stress in the weld and reduce the distribution range of longitudinal tensile stress.And the welding deformation also decreases to some extent.
文摘A new hybrid welding process was successfully used to join aluminum alloy and stainless steel. In the MIG welding-brazing process, the lower thermal conductivity of steel can cause dramatic change of temperature gradient on steel surface, while the auxiliary TIG arc can change this phenomenon by heating the steel side. The auxiliary TIG improved the wettability of molten metal, resulting in the molten metal spreading fully on upper surfaces, front and back surface of steel, forming a sound brazing joint; the content of Cr and Ni elements in IMCs layer was increased, which can enhance the quality of the layer; and the microstructure of IMCs layer also was improved, increasing the bonding strength with the weld seam. The average tensile strength of the joint obtained with auxiliary TIG arc（146.7 MPa） was higher than that without auxiliary TIG arc（96.7 MPa）.
基金Project(51405398) supported by the National Natural Science Foundation of China
文摘Laser-metal inert-gas(MIG)hybrid welding-brazing was applied to the butt joint of 6061-T6 aluminum alloy and 304 stainless steel.The microstructure and mechanical properties of the joint were studied.An excellent joint-section shape was achieved from good wettability on both sides of the stainless steel.Scanning electron microscopy,energy-dispersive spectroscopy and X-ray diffractometry indicated an intermetallic compound(IMC)layer at the 6061-T6/304 interface.The IMC thickness was controlled to be^2μm,which was attributed to the advantage of the laser-MIG hybrid method.Fe3Al dominated in the IMC layer at the interface between the stainless steel and the back reinforcement.The IMC layer in the remaining regions consisted mainly of Fe4Al13.A thinner IMC layer and better wettability on both sides of the stainless steel were obtained,because of the optimized energy distribution from a combination of a laser beam with a MIG arc.The average tensile strength of the joint with reinforcement using laser-MIG hybrid process was improved to be 174 MPa(60%of the 6061-T6 tensile strength),which was significantly higher than that of the joint by traditional MIG process.
