轧制对AZ31/AZ91焊接接头组织及扩散的影响

Influence of rolling on microstructure and diffusion of AZ31 /AZ91 welded joint

为了理解异种镁合金焊接接头显微组织的变化规律,采用TIG焊接方法制备了AZ31/AZ91焊接接头,研究了轧制变形及热处理对AZ31/AZ91焊接接头显微组织及扩散系数的影响.结果表明,随着轧制变形量的增加,AZ31/AZ91熔合区的晶粒细化程度增大,但在随后的420℃×8 h固溶处理过程中,由于再结晶充分,因此晶粒逐渐变大.在420℃×2 h固溶处理过程中,Al的扩散系数随轧制变形量的增加而增大;在420℃×8 h固溶处理条件下,Al的扩散系数随轧制变形量的增加而减小.相同轧制变形量下,Al的扩散系数随着保温时间的增加而减小.

In order to understand the variation rule in the microstructure of dissimilar magnesium alloy welded joint, the AZ31/AZ91 welded joint was prepared with TIG welding method, and the influence of both rolling reduction and heat treatment on the microstructure and diffusion coefficient of AZ31/AZ91 welded joint was studied. The results show that with increasing the rolling reduction, the refinement degree of grains within the fusion zone of AZ31/AZ91 welded joint increases, while the grain size gradually becomes larger due to the full recrystallization after the solid-solution treatment at 420℃ for 8 h. During the solid-solution treatment at 420℃ for 2 h, the diffusion coefficient of Al will increase with increasing the rolling reduction. During the solid-solution treatment at 420℃ for 8 h, the diffusion coefficient of Al will decrease with increasing the rolling reduction. Under the same rolling reduction, the diffusion coefficient of Al will decrease with increasing the holding time.