置氢0.55%对电弧增材制造TC4钛合金组织的影响

Influence of 0.55wt% Hydrogenation on the Microstructure of TC4 Titanium Alloy by Wire Arc Additive Manufacturing

研究了置氢0.55%(质量分数)的电弧增材制造TC4钛合金经过Hydrovac(HVC)氢化处理后组织的演变规律。结果表明,电弧增材制造技术制备的TC4钛合金,组织形貌为粗大的柱状β晶,且晶粒内部为片层α集束。经过置氢处理后,由于氢的扩散和对晶界腐蚀的作用,使β晶内部片层α集束变得更加细小,且有氢化物产生。随后在温度810℃下对置氢钛合金进行淬火,组织中生成了α′、α″和亚稳相β_(M)。并在后续的时效除氢过程中,随着马氏体、亚稳相和氢化物的分解,使钛合金组织中柱状β晶内的片层α晶粒得到显著细化,形成交错分布的细针状组织。

The evolution of the microstructure of the wire arc additive manufactured TC4 titanium alloy wi th a hydrogen content of 0.55wt% after HVC hydrogen treatment was studied.The results show that the microstructure of TC4 titanium alloy produced by wire arc additive manufacturing technology is coarse columnar β crystals,and the inside of the crystal grains is lamellarαclusters.After the hydrogenation treatment,due to the diffusion of hydrogen and the effect of the grain boundary corrosion,the inner layer of the β crystal becomes smaller and the hydride is produced.Subsequently,the hydrogenated titanium alloy was quenched at 810℃,and α′,α″and metastable phase β_(M) are formed in the structure.In the process of aging and hydrogen removal,with the decomposition of martensite,metastable phase and hydride,the lamellarαgrains in the columnar β crystals are significantly refined,forming a staggered fine needle-like microstructure.