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以Cu箔为中间夹层对AZ31B镁合金与304不锈钢进行瞬间液相扩散连接,研究了焊接接头的微观结构和连接强度。结果表明,在510℃/30 min、530℃/10 min下进行扩散连接时,接头界面区没有出现共晶液相,界面结合较弱;520℃/30 min、530℃/20 min时,接头界面区形成Mg-Cu共晶液相,焊缝宽度显著增加,界面结合强度提高;530℃/30min时,镁基体一侧形成350μm的层状扩散区,接头显微组织依次是Mg-Cu共晶组织层、富Mg固溶体层、弥散分布于镁合金基体的Mg17(Cu,Al)12相和分布于镁合金晶界的Mg-Cu-Al三元化合物所组成的镁合金基体渗透区,其剪切强度达到最大(52 MPa);540℃/30 min、530℃/40 min时,界面扩散区的共晶液相发生等温凝固,镁合金基体晶界处Mg-Cu-Al三元金属间化合物呈连续网状分布,接头的剪切强度降低。AZ31B基体发生了再结晶及晶粒长大。
The instantaneous liquid phase diffusion bonding between AZ31B magnesium alloy and 304 stainless steel was carried out by using Cu foil as the interlayer to study the microstructure and bonding strength of the welded joints. The results show that there is no eutectic liquid phase in the interface of the joint at 510 ℃ / 30 min and 530 ℃ / 10 min, and the interface bonding is weak. At 520 ℃ / 30 min and 530 ℃ / 20 min, Mg-Cu eutectic liquid phase was formed in the interface region, the width of the weld joint was significantly increased, and the interfacial bonding strength was increased. At 530 ℃ / 30min, a 350μm layered diffusion zone was formed on one side of the Mg matrix. Mg-Cu solid solution layer, Mg17 (Cu, Al) 12 phase dispersedly distributed in the magnesium alloy matrix, and Mg-Cu-Al ternary compound distributed in the grain boundaries of the magnesium alloy, The shear strength reached the maximum (52 MPa). At 540 ℃ for 30 min and 530 ℃ for 40 min, the eutectic liquid phase in the interface diffusion zone was isothermally solidified. The Mg-Cu-Al ternary intermetallics The compounds showed a continuous network distribution and the shear strength of the linker decreased. AZ31B matrix recrystallization and grain growth.