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
The corrosion kinetics and patina(corrosion products) layer evolution of galvanized steel submitted to wet/dry cyclic corrosion test in a simulated coastal-industrial atmosphere was investigated. The results show that...The corrosion kinetics and patina(corrosion products) layer evolution of galvanized steel submitted to wet/dry cyclic corrosion test in a simulated coastal-industrial atmosphere was investigated. The results show that zinc coating has a greater corrosion rate during the initial period and a lower corrosion rate during the subsequent period, and the patina composition and structure can greatly affect the corrosion kinetics evolution of zinc coating. Moreover, Zn5(OH)6(CO3)2 and Zn4(OH)6 SO4 are identified as the main stable composition and exhibit an increasing relative amount;while Zn12(OH)15Cl3(SO4)3 cannot stably exist and diminish in the patina layer as the corrosion develops.展开更多
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.
基金supported by the National Natural Science Fundation of China (Nos. 51501204 and 51671200)the Research Program of Corrosion Distribution and Anti-corrosion Measures of Power Transmission in Complex Atmospheric Environment of Large Coastal Cities (No. GZM2014-2-0004)the Science and Technology Department of Henan Province (No. 172102310726)
文摘The corrosion kinetics and patina(corrosion products) layer evolution of galvanized steel submitted to wet/dry cyclic corrosion test in a simulated coastal-industrial atmosphere was investigated. The results show that zinc coating has a greater corrosion rate during the initial period and a lower corrosion rate during the subsequent period, and the patina composition and structure can greatly affect the corrosion kinetics evolution of zinc coating. Moreover, Zn5(OH)6(CO3)2 and Zn4(OH)6 SO4 are identified as the main stable composition and exhibit an increasing relative amount;while Zn12(OH)15Cl3(SO4)3 cannot stably exist and diminish in the patina layer as the corrosion develops.
