在TC4粉中加入不同含量的硼粉进行激光增材制造试验,研究了硼对激光增材制造TC4钛合金微观组织及力学性能的影响。结果表明:添加微量硼可以有效细化原始柱状晶和晶内的板条α相;当硼的质量分数为0.05%时,原始β柱状晶的生长被限制,柱状晶的宽度明显减小;当硼的质量分数为0.1%时,原始柱状晶大量转变为等轴晶,晶内板条α集束的尺寸减小;对比没有添加硼的激光增材制造TC4,TC4-0.05B的塑性明显提高,但强度的变化不明显;沉积态和固溶时效态TC4-0.05B力学性能的各向异性都较小。

In this study, B powders of different contents are added into TC4 powders and the laser additive manufacturing (LAM) experiment is conducted. Influence of the addition of B on the microstructure and mechanical properties of samples is investigated. Results show that the addition of trace B can effectively refine the microstructure size of TC4 alloy produced using LAM. The growth of the prior-β grains in LAM-TC4 alloy is restrained by an addition of 0.05% B, and the grain width is significantly decreased. An addition of 0.1% B can promote the transformation from coarse prior-β crystals to equiaxed crystals and result in a great reduction of the size of α bundle. Plasticity of the TC4-0.05B alloy is evidently improved compared with that of the boron-free TC4 alloy, whereas the change in the strength is not significant. Anisotropy of the as-deposited TC4-0.05B alloy and TC4-0.05B-solution aging is low.