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电弧增材制造钛合金构件中容易形成粗大柱状晶,导致组织和力学性能的各向异性,为了解决这一问题,拟采用超声冲击与电弧增材制造相结合来改变内部组织以实现性能的优化。研究发现,超声冲击能够使钛合金沉积层内部的粗大柱状晶转变为细小等轴晶。同时,其抗拉强度各向异性百分比由12.5%缩减为1.5%。超声冲击促进了沉积层的位错增殖及迁移,造成晶粒破碎的同时增多了形核质点。这些新增质点改变了形核环境,提高了变形储能,在后续沉积层热作用下通过回复再结晶和相变形成细小的等轴晶。
In order to solve this problem, it is proposed that the combination of ultrasonic impact and arc additive manufacturing be used to change the internal structure to optimize the performance. In order to solve the problem, it is easy to form coarse columnar crystals in the arc additive manufacturing of titanium alloy members, resulting in the anisotropy of the microstructure and mechanical properties. . It was found that the ultrasonic shock can transform the coarse columnar crystals in the titanium alloy deposit into fine equiaxed grains. At the same time, the percentage of tensile strength anisotropy was reduced from 12.5% to 1.5%. Ultrasonic impact promotes the dislocation proliferation and migration of the sedimentary layer, resulting in the increase of nucleation particles while the crystal grains are broken. These new particles change the nucleation environment, improve the deformation energy storage, and form minor equiaxed grains through the recrystallization and phase transformation after the subsequent depositional layer thermal action.