CMT电弧熔丝增材制造AZ31镁合金组织与性能调控研究

Study on the regulation of microstructure and mechanical properties of WAAM-CMT AZ31 magnesium alloy

冷金属过渡(CMT)电弧熔丝增材制造镁合金具有广阔的应用前景,但存在微观组织不均匀、力学性能各向异性等问题。文中以AZ31镁合金为研究对象,探索不同输入能量密度对宏观成形质量的影响,分析微观组织演化规律并对其力学性能进行调控。结果表明,在合适能量密度下可成形出表面平整、无明显宏观冶金缺陷的镁合金试样,沉积态试样的底部、中部和顶部微观组织存在显著差异。固溶热处理后,枝晶间的粗大组织得到消除,试样在水平和竖直方向上的强度和塑性明显提升,力学性能各向异性得到有效改善。研究结果为CMT电弧增材制造强韧性匹配镁合金提供了技术参考。

Wire arc additive manufacturing( WAAM) of magnesium alloy using cold metal transfer process( CMT) has promising applications. However, there are still problems such as non-uniform microstructure and anisotropy of mechanical properties. In this paper,the AZ31 magnesium alloy was taken as the research object. The effects of different arc energy densities on the macroscopic fabrication quality were explored,the microstructure evolution was analyzed and the mechanical properties were regulated. The results showed that the AZ31magnesium alloy samples with flat surface and no obvious metallurgical defects could be formed at a suitable energy density,and the microstructure of the bottom,middle and top of the deposited samples were significantly different. After the solution heat treatment,the coarse microstructure between the dendrites was eliminated,the strength and plasticity in the horizontal and vertical directions were significantly increased,and the anisotropy of mechanical properties was effectively improved. This study provided a technical reference for WAAM-CMT forming magnesium alloy with strong toughness matching.