Abstract 6061/7N01 dissimilar aluminum alloys were welded by the cold metal transfer plus pulse (CMT + P) technology. With a decrease in the ratio of number of CMT stages to P stages in one CMT + P cycle (CMT/P ratio), the heat input increased and grain growth was observed in the weld metal. The grains in the heat-affected zone (HAZ) were equiaxed on the 6061 side, and the grains in the HAZ on the 7N01 side retained their strip shape. As the CMT/P ratio decreased, the widths of the partially melted zone (PMZ) and HAZ on both sides increased. Asymmetric hardness distribution profiles were observed for all the samples due to the obvious differences in the microstructure of the two base metals. Micro-hardness exhibited an increasing tendency from the HAZ to the PMZ on the 6061 side. The changes in the trend of micro-hardness on the 7N01 side were opposite of those on the 6061 side due to the adverse effect of Si impurities. When the ratio of CMT/P was 1:7, the strength of the weld joint was approximately 60% of the strength of the 6061 substrate due to the transformation and coarsening of the strengthening phase. The fracture site is located in the HAZ on the 6061 side. Dimples were uniformly distributed on the fracture surfaces, which indicates a typical ductile fracture.

中文翻译：

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6061/7N01 CMT+P接头的显微组织和力学性能

摘要 采用冷金属转移加脉冲（CMT+P）技术焊接6061/7N01异种铝合金。随着一个 CMT+P 循环中 CMT 阶段数与 P 阶段数的比率（CMT/P 比率）的减少，热输入增加，并且在焊缝金属中观察到晶粒生长。热影响区 (HAZ) 中的晶粒在 6061 侧等轴化，而热影响区中的晶粒在 7N01 侧保持带状。随着 CMT/P 比值的降低，部分熔化区 (PMZ) 和两侧 HAZ 的宽度增加。由于两种母材的微观结构存在明显差异，因此所有样品均观察到不对称的硬度分布曲线。显微硬度从 HAZ 到 6061 侧的 PMZ 呈增加趋势。由于Si杂质的不利影响，7N01侧显微硬度的变化趋势与6061侧相反。当CMT/P比为1:7时，由于强化相的转变和粗化，焊接接头的强度约为6061基体强度的60%。断裂部位位于 6061 侧的 HAZ。断口上均匀分布有凹坑，为典型的韧性断裂。