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使用AZ61和AZ91焊丝TIG焊AZ91B镁合金均可获得组织致密、焊缝与母材结合良好的焊接接头。焊缝组织由分枝发达、呈雪化状的α枝晶以及晶间 (α +Mg17Al12 )低熔点共晶体组成 ;熔合区组织由细小的α Mg等轴晶和晶间共晶体组成 ;热影响区组织接近母材 ,由粗大的α Mg树枝晶和分布于其间的α +Mg17Al12 共晶体组成。由于焊接过程中镁的过热蒸发 ,导致焊缝相对含Al量升高 ,共晶体含量增多 ,从而使焊缝热裂纹倾向增大。使用ERAZ61焊接AZ91B合金更易获得抗热裂性能高、与母材成分和组织一致性好的接头 ;而且接头抗拉强度和伸长率也较高
Using AZ61 and AZ91 welding wire TIG welding AZ91B magnesium alloy can be obtained with dense tissue, welded joint and the base metal well welded joints. The microstructure of the weld consists of a branched dendritic α-dendrite and an intergranular (α + Mg17Al12) low melting point eutectic. The fusion zone consists of fine α Mg equiaxed and intergranular eutectic; The zone organization is close to the base metal and consists of coarse α Mg dendrites and α + Mg 17 Al 12 co-crystals interspersed therebetween. Due to superheated evaporation of magnesium during welding, the relative amount of Al in the weld increases and the eutectic content increases, thus increasing the hot crack tendency of the weld. The use of ERAZ61 AZ91B alloy welding easier access to hot cracking performance, and the base metal composition and organization of good joints; and joint tensile strength and elongation are also higher