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
A galvanized steel is used to join Mg AZ31B alloy and Al A6061-T6 alloy as a joining transition layer by cold metal transfer(CMT)method.Firstly,to optimize the process variables,extensive welding tests were performed ...A galvanized steel is used to join Mg AZ31B alloy and Al A6061-T6 alloy as a joining transition layer by cold metal transfer(CMT)method.Firstly,to optimize the process variables,extensive welding tests were performed by a design of experiment method.Then,microstructures,joining mechanisms and tensile properties were characterized and analyzed.Results indicated that Mg and Al alloys can be joined by using galvanized steel as a joining transition layer and cold metal transfer welding method.The formed joint is called as a Mg–steel–Al CMT joint.By using galvanized steel transition joining layer,Mg–Al brittle intermetallics Al12Mg17 and Al3Mg2 were inhibited.The properties of Mg–steel–Al CMT joints have been improved after optimizing the welding variables.The strength of Mg–steel–Al CMT joint is comparable to those of Al–Al joint and Mg–Mg joint.The strength of Mg–steel–Al CMT joint can reach 100%that of Al–Al joint and Al–steel joint,and reach 90%that of Mg–Mg joint and Mg–steel joint.The optimized Mg–steel–Al CMT welded joint with galvanized steel transition layer is fractured at the heat affected zone of Al base metal rather than at the weld-brazed interface,due to softening of Al base metal.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).
基金National Natural Science Foundation of China(Nos.51761027 and 51675255)the Foundation of Collaborative Innovation Teams in College of Gansu Province(2017C-07)Lanzhou Science and Technology Department Project(2019-1-49).
文摘A galvanized steel is used to join Mg AZ31B alloy and Al A6061-T6 alloy as a joining transition layer by cold metal transfer(CMT)method.Firstly,to optimize the process variables,extensive welding tests were performed by a design of experiment method.Then,microstructures,joining mechanisms and tensile properties were characterized and analyzed.Results indicated that Mg and Al alloys can be joined by using galvanized steel as a joining transition layer and cold metal transfer welding method.The formed joint is called as a Mg–steel–Al CMT joint.By using galvanized steel transition joining layer,Mg–Al brittle intermetallics Al12Mg17 and Al3Mg2 were inhibited.The properties of Mg–steel–Al CMT joints have been improved after optimizing the welding variables.The strength of Mg–steel–Al CMT joint is comparable to those of Al–Al joint and Mg–Mg joint.The strength of Mg–steel–Al CMT joint can reach 100%that of Al–Al joint and Al–steel joint,and reach 90%that of Mg–Mg joint and Mg–steel joint.The optimized Mg–steel–Al CMT welded joint with galvanized steel transition layer is fractured at the heat affected zone of Al base metal rather than at the weld-brazed interface,due to softening of Al base metal.
