针对激光熔覆沉积TC4钛合金力学性能较低,不能达到锻件标准且力学性能各向异性较大的问题,通过机械搅拌预制不同硼含量的TC4粉体,使用预制粉体进行激光熔覆沉积实验,以达到调控微观组织、提高综合力学性能的目的。结果表明:当硼质量分数为0.050%时,沉积态TC4钛合金的力学性能均超过锻件标准,屈服强度和抗拉强度分别为1049 MPa和1136 MPa,延伸率和断面收缩率分别达到11.50%和33.5%,但塑性各向异性高达30%以上;经过950 ℃×1 h/空冷+500 ℃×4 h/空冷固溶时效热处理后,综合力学性能进一步提高,在保证强度的同时,延伸率和断面收缩率分别达到16.70%和37.3%,且各向异性小于5%。

The laser-cladding-deposited TC4 titanium alloy is considerably anisotropic, and its mechanical properties are lower than the forging standards. In this study, boron (B) with different mass fractions is uniformly mixed into the TC4 powder by mechanical stirring, refining the microstructure and improving the comprehensive mechanical properties of the alloy. Results show that at a B mass fraction of 0.050%, the mechanical properties of the deposited TC4 titanium alloy exceed the forging standard, and the yield and tensile strengths become 1049 MPa and 1136 MPa, respectively. Furthermore, the elongation and area reduction become 11.50% and 33.5%, respectively, though the plastic anisotropy is larger than 30%. After solid solution and aging heat treatment with 950 ℃×1 h/air cooling +500 ℃×4 h/air cooling, the comprehensive mechanical properties are further optimized and the anisotropy is reduced to less than 5%. While we ensure suitable mechanical strength, the elongation and area reduction are enhanced to 16.70% and 37.3%, respectively.