电弧3D打印TC4钛合金的组织与性能研究

Study on Microstructure and Mechanical Properties of Arc 3D Printing TC4 Titanium Alloy

采用冷金属过渡(Cold metal transfer,CMT)焊接技术制备了TC4钛合金件,研究了TC4钛合金增材体的显微组织和力学性能。结果表明:TC4钛合金打印态的表面成形良好,电弧3D打印TC4钛合金高度方向宏观组织上为外延生长的粗大β柱状晶形态,组织由α相和β相组成。增材体的顶部为针状马氏体区,中部为细小的层片状网篮组织,基材结合处主要由层片状组织、β相以及少量残余α'相组成。所制备的成形件硬度较基材的高,表层部分硬度最大。室温拉伸性能呈现出明显的各向异性,水平方向拉伸强度较高,沿增材高度方向的塑性较高。室温冲击韧度未呈现出明显的各向异性,Aku2均达到70 J/cm2。

TC4 titanium alloy block was prepared by using cold metal transfer(CMT)welding technology.The microstructure and mechanical properties of the alloy were investigated.The results indicate that the surface forming of TC4 titanium alloy in pringting state is good.The microstructure of arc 3D printing TC4 titanium alloy sample is coarse columnar grains epitaxially growing from the substrate in vertical direction,which is composed ofαandβphases.The area of acicular martensite locates the upper portion of the additional material,basket-weave structure with fine tabular at middle part and the base bonding place is mainly composed of lamellar structure,βphase and a small amount of residualα'phase.The hardness of the prepared forming part is higher than that of the substrate,the hardness of the surface is the highest.The room temperature tensile properties show obvious anisotropy and the tensile strength along the horizontal direction is better,the plasticity along the height direction of additive is better.The room temperature impact toughness has no significant anisotropy,and the impact value Aku2 reaches 70 J/cm2.