(兰州理工大学 有色金属合金及加工教育部重点实验室，兰州 730050)
摘 要:
关键字: AZ31B镁合金；AZ61A镁合金；搅拌摩擦焊；力学性能；层状组织
AZ31B and AZ61A magnesium alloy
（Key Laboratory of Advanced Non-ferrous Alloy and Processing, Ministry of Education,
Lanzhou University of Technology, Lanzhou 730050, China）
Abstract:Dissimilar AZ61A and AZ31B magnesium alloys were welded with friction stir welding. The influence of welding parameters on the microstructure and mechanical properties of the joint was investigated. Experimental results show that when using concave round platform tool and placing AZ31B at the retreating side, the beautiful welded joints without discontinuity are easily obtained. The maximum tensile strength of joint can reach 90.5% that of the AZ31B base material. The microstructure analysis of joint reveals that the microstructures of the various regions are very different, and the microstructure distribution is layered and wide on the mechanical heat-affected zone. When the process parameters are not appropriate, the oxide and impurity congregate between the layered microstructures. The existence of the impure stratum structure and stress concentration is the main reason that causes the drop of mechanical properties in the mechanical heat-affected zone.
Key words: AZ31B magnesium alloy; AZ61Amagnesium alloy; friction stir welding; mechanical properties; stratum structure
