The corrosion performance of aluminum/steel contact and aluminum/steel FSW joint in 3.5 wt.%NaCl solution were analyzed using potentiostatic tests.The post-corrosion microstructure of the welding joint was characteriz...The corrosion performance of aluminum/steel contact and aluminum/steel FSW joint in 3.5 wt.%NaCl solution were analyzed using potentiostatic tests.The post-corrosion microstructure of the welding joint was characterized by optical microscope(OM),scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS).The results showed that the localized corrosion of FSW joint of Al/steel dissimilar metals mainly initiated at the interface transition zone(ITZ).Precipitation of intermetallic compounds(IMCs)and Fe-rich phase particles in ITZ accelerated the corrosion of the FSW joint.This phenomenon has been attributed to distinct corrosion potentials between IMCs and steel,aluminum base metal.The corrosion resistance sequence of IMCs in ITZ is Fe_(3)Al>FeAl>Fe_(2)Al_(5).展开更多
Micro welding of dissimilar metals can meet many performance requirements for modern engineering structures. In this experiment, laser micro welding of copper-aluminum dissimilar metals was conducted with an HWLW-300A...Micro welding of dissimilar metals can meet many performance requirements for modern engineering structures. In this experiment, laser micro welding of copper-aluminum dissimilar metals was conducted with an HWLW-300A energy negative feedback Nd:YAG pulse laser. By using the overlap welding method with copper on aluminum, with the laser energy being distributed unevenly, good weld joints were obtained. In this paper, the welding mechanism was analyzed from aspects such as welding temperature and the specific heat capacity of the solid metal. Existing defects were identified, and a feasible improvement scheme was proposed.展开更多
This paper mainly concentrated on the feasibility of friction stir welding of dissimilar metal of aluminum alloy to copper （I2） and a preliminary analysis of welding parameters influencing on the microstructures and...This paper mainly concentrated on the feasibility of friction stir welding of dissimilar metal of aluminum alloy to copper （I2） and a preliminary analysis of welding parameters influencing on the microstructures and properties of joint was carried out. The results indicated that the thickness of workpiece played an important role in the welding parameters which could succeed in the friction stir welding of dissimilar metal of copper to aluminum alloy, and the parameters were proved to be a narrow choice. The interfacial region between copper and aluminum in the dissimilar joint was not uniformly mixed, constituted with part of incomplete mixing zone, complete mixing zone, dispersion zone and the most region＇ s boundary was obvious. Meantime a kind banded structure with inhomogeneous width was formed. The intermetallic compounds generated during friction stir welding in the interfacial region were mainly CugAl4, Al2Cu etc, and their hardness was higher than oihers.展开更多
Dissimilar friction stir welding between 5052 Al alloy and AZ31 Mg alloy with the plate thickness of 6 mm was investigated.Sound weld was obtained at rotation speed of 600 r/min and welding speed of 40 mm/min.Compared...Dissimilar friction stir welding between 5052 Al alloy and AZ31 Mg alloy with the plate thickness of 6 mm was investigated.Sound weld was obtained at rotation speed of 600 r/min and welding speed of 40 mm/min.Compared with the base materials,the microstructure of the stir zone is greatly refined.Complex flow pattern characterized by intercalation lamellae is formed in the stir zone.Microhardness measurement of the dissimilar welds presents an uneven distribution due to the complicated microstructure of the weld,and the maximum value of microhardness in the stir zone is twice higher than that of the base materials. The tensile fracture position locates at the advancing side(aluminum side),where the hardness distribution of weld shows a sharp decrease from the stir zone to 5052 base material.展开更多
Dissimilar metal joining between 5A02 aluminum alloy and H62 brass sheets was conducted by gas tungsten arc welding with Zn-15% Al and Al-12% Si flux-cored filler wires. The microstructure in the weld and distribution...Dissimilar metal joining between 5A02 aluminum alloy and H62 brass sheets was conducted by gas tungsten arc welding with Zn-15% Al and Al-12% Si flux-cored filler wires. The microstructure in the weld and distribution of major alloying elements in the intelfacial layer were examined, and the tensile strength of the resultant joints was measured. Pores appeared in the weld made with Zn-15% Al flax-cored filler wire, the interracial layer mainly consisted of AlCu phase, and the specimens fractured through the weld with tensile strength of 129 MPa. When Al-12% Si flux-cored filler wire was used, Cu diffused into the weld and Al2 Cu phase formed, and the specimens fractured along the interfacial layer with tensile strength of 122 MPa.展开更多
Joining Mg to Al is challenging because of the deterioration of mechanical properties caused by the formation of intermetallic compounds(IMCs) at the Mg/Al interface. This study aims to improve the mechanical properti...Joining Mg to Al is challenging because of the deterioration of mechanical properties caused by the formation of intermetallic compounds(IMCs) at the Mg/Al interface. This study aims to improve the mechanical properties of welded samples by preventing the fracture location at the Mg/Al interface. Friction stir welding was performed to join Mg to Al at different rotational and travel speeds. The microstructure of the welded samples showed the IMCs layers containing Al12Mg17(γ) and Al3Mg2(β) at the welding zone with a thickness(< 3.5 μm). Mechanical properties were mainly affected by the thickness of the IMCs, which was governed by welding parameters. The highest tensile strength was obtained at 600 r/min and 40 mm/min with a welding efficiency of 80%. The specimens could fracture along the boundary at the thermo-mechanically affected zone in the Mg side of the welded joint.展开更多
The synthesis, processing and mechanical properties of the light metals, aluminum,magnesium and titanium Produced by advanced techniques are reviewed. Synthesis techniques to be addressed will include rapid solidifica...The synthesis, processing and mechanical properties of the light metals, aluminum,magnesium and titanium Produced by advanced techniques are reviewed. Synthesis techniques to be addressed will include rapid solidification, spray deposition, mechanical alloying, plasma Processing and vapor deposition.展开更多
A novel joining method,double-stage diffusion-brazing of an AZ31 magnesium alloy and a 304L austenitic stainless steel,was carried out using a pure copper interlayer.The solid-state diffusion bonding of 304L to copper...A novel joining method,double-stage diffusion-brazing of an AZ31 magnesium alloy and a 304L austenitic stainless steel,was carried out using a pure copper interlayer.The solid-state diffusion bonding of 304L to copper was conducted at 850 ℃ for 20 min followed by brazing to AZ31 at 520 ℃ and 495 ℃ for various time.Microstructural characteristics of the diffusion-brazed joints were investigated in detail.A defect free interface of Fe-Cu diffusion area appeared between the Cu alloy and the 304L steel.Cu-Mg reaction products were formed between AZ31 and Cu alloys.A layered structure including AZ31/Cu-Mg compounds/Cu/Fe-Cu diffusion layer/304L was present in the joint.With time prolonging,the reduction in the width of Cu layer was balanced by the increase in the width of Cu-Mg compounds zone.Microhardness peaks in the zone between AZ31 and Cu layer were attributed to the formation of Mg-Cu compounds in this zone.展开更多
The effects of laser parameters and interlayer material on the microstructure and properties of the welded joint between 6061 aluminum alloy and stainless steel were studied.The results show that the density and micro...The effects of laser parameters and interlayer material on the microstructure and properties of the welded joint between 6061 aluminum alloy and stainless steel were studied.The results show that the density and microstructure of the welded joint can be optimized by changing the laser power with 0.05 mm Cu foil and 0.1 mm Ni foil as interlayer.A large number of new Cu-Al binary phases were found near the aluminum alloy,which effectively inhibited the formation of the binary brittle phase of Fe-Al.The maximum shear force of 1350.96 N was obtained with laser power of 2200 W.The shear force of the welded joint increased to 1754.73 N when the thickness of the Cu foil thickness changed to 0.02 mm.展开更多
基金supported by the Natural Science Foundation of Hebei(Grant No.E2019210292)Education Department of Hebei(Grant No.ZD2019102).
文摘The corrosion performance of aluminum/steel contact and aluminum/steel FSW joint in 3.5 wt.%NaCl solution were analyzed using potentiostatic tests.The post-corrosion microstructure of the welding joint was characterized by optical microscope(OM),scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS).The results showed that the localized corrosion of FSW joint of Al/steel dissimilar metals mainly initiated at the interface transition zone(ITZ).Precipitation of intermetallic compounds(IMCs)and Fe-rich phase particles in ITZ accelerated the corrosion of the FSW joint.This phenomenon has been attributed to distinct corrosion potentials between IMCs and steel,aluminum base metal.The corrosion resistance sequence of IMCs in ITZ is Fe_(3)Al>FeAl>Fe_(2)Al_(5).
文摘Micro welding of dissimilar metals can meet many performance requirements for modern engineering structures. In this experiment, laser micro welding of copper-aluminum dissimilar metals was conducted with an HWLW-300A energy negative feedback Nd:YAG pulse laser. By using the overlap welding method with copper on aluminum, with the laser energy being distributed unevenly, good weld joints were obtained. In this paper, the welding mechanism was analyzed from aspects such as welding temperature and the specific heat capacity of the solid metal. Existing defects were identified, and a feasible improvement scheme was proposed.
基金This project is supported by National Natural Science Foundation of China ( NSFC)(10577010)
文摘This paper mainly concentrated on the feasibility of friction stir welding of dissimilar metal of aluminum alloy to copper （I2） and a preliminary analysis of welding parameters influencing on the microstructures and properties of joint was carried out. The results indicated that the thickness of workpiece played an important role in the welding parameters which could succeed in the friction stir welding of dissimilar metal of copper to aluminum alloy, and the parameters were proved to be a narrow choice. The interfacial region between copper and aluminum in the dissimilar joint was not uniformly mixed, constituted with part of incomplete mixing zone, complete mixing zone, dispersion zone and the most region＇ s boundary was obvious. Meantime a kind banded structure with inhomogeneous width was formed. The intermetallic compounds generated during friction stir welding in the interfacial region were mainly CugAl4, Al2Cu etc, and their hardness was higher than oihers.
基金Project(B01B7070270)supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry,China
文摘Dissimilar friction stir welding between 5052 Al alloy and AZ31 Mg alloy with the plate thickness of 6 mm was investigated.Sound weld was obtained at rotation speed of 600 r/min and welding speed of 40 mm/min.Compared with the base materials,the microstructure of the stir zone is greatly refined.Complex flow pattern characterized by intercalation lamellae is formed in the stir zone.Microhardness measurement of the dissimilar welds presents an uneven distribution due to the complicated microstructure of the weld,and the maximum value of microhardness in the stir zone is twice higher than that of the base materials. The tensile fracture position locates at the advancing side(aluminum side),where the hardness distribution of weld shows a sharp decrease from the stir zone to 5052 base material.
基金Acknowledgements This work was financially supported by the National Natural Science Foundation of China （ Grant No. 50904012 ） and Natural Science Foundation of Liaoning Province （Grant No. 20092152）.
文摘Dissimilar metal joining between 5A02 aluminum alloy and H62 brass sheets was conducted by gas tungsten arc welding with Zn-15% Al and Al-12% Si flux-cored filler wires. The microstructure in the weld and distribution of major alloying elements in the intelfacial layer were examined, and the tensile strength of the resultant joints was measured. Pores appeared in the weld made with Zn-15% Al flax-cored filler wire, the interracial layer mainly consisted of AlCu phase, and the specimens fractured through the weld with tensile strength of 129 MPa. When Al-12% Si flux-cored filler wire was used, Cu diffused into the weld and Al2 Cu phase formed, and the specimens fractured along the interfacial layer with tensile strength of 122 MPa.
基金Universiti Kebangsaan Malaysia for supporting this research project through the research funding (AP-2015-016)
文摘Joining Mg to Al is challenging because of the deterioration of mechanical properties caused by the formation of intermetallic compounds(IMCs) at the Mg/Al interface. This study aims to improve the mechanical properties of welded samples by preventing the fracture location at the Mg/Al interface. Friction stir welding was performed to join Mg to Al at different rotational and travel speeds. The microstructure of the welded samples showed the IMCs layers containing Al12Mg17(γ) and Al3Mg2(β) at the welding zone with a thickness(< 3.5 μm). Mechanical properties were mainly affected by the thickness of the IMCs, which was governed by welding parameters. The highest tensile strength was obtained at 600 r/min and 40 mm/min with a welding efficiency of 80%. The specimens could fracture along the boundary at the thermo-mechanically affected zone in the Mg side of the welded joint.
文摘The synthesis, processing and mechanical properties of the light metals, aluminum,magnesium and titanium Produced by advanced techniques are reviewed. Synthesis techniques to be addressed will include rapid solidification, spray deposition, mechanical alloying, plasma Processing and vapor deposition.
基金Project(51205428) supported by the National Natural Science Foundation of ChinaProject(CDJRC10130011) supported by the Fundamental Research Funds for the Central Universities,China
文摘A novel joining method,double-stage diffusion-brazing of an AZ31 magnesium alloy and a 304L austenitic stainless steel,was carried out using a pure copper interlayer.The solid-state diffusion bonding of 304L to copper was conducted at 850 ℃ for 20 min followed by brazing to AZ31 at 520 ℃ and 495 ℃ for various time.Microstructural characteristics of the diffusion-brazed joints were investigated in detail.A defect free interface of Fe-Cu diffusion area appeared between the Cu alloy and the 304L steel.Cu-Mg reaction products were formed between AZ31 and Cu alloys.A layered structure including AZ31/Cu-Mg compounds/Cu/Fe-Cu diffusion layer/304L was present in the joint.With time prolonging,the reduction in the width of Cu layer was balanced by the increase in the width of Cu-Mg compounds zone.Microhardness peaks in the zone between AZ31 and Cu layer were attributed to the formation of Mg-Cu compounds in this zone.
基金financially supported by the National Natural Science Foundation of China(No.51704001)the Natural Science Foundation of Anhui Province,China(No.2008085J23)the Talent Project of Anhui Province,China(Z175050020001)。
文摘The effects of laser parameters and interlayer material on the microstructure and properties of the welded joint between 6061 aluminum alloy and stainless steel were studied.The results show that the density and microstructure of the welded joint can be optimized by changing the laser power with 0.05 mm Cu foil and 0.1 mm Ni foil as interlayer.A large number of new Cu-Al binary phases were found near the aluminum alloy,which effectively inhibited the formation of the binary brittle phase of Fe-Al.The maximum shear force of 1350.96 N was obtained with laser power of 2200 W.The shear force of the welded joint increased to 1754.73 N when the thickness of the Cu foil thickness changed to 0.02 mm.
