置氢0.55wt.%对电弧增材制造TC4钛合金组织影响的研究

Study on the influence of 0.55wt.% hydrogenation on the microstructure of TC4 titanium alloy by wire arc additive manufacturing

摘要:

本文研究了置氢0.55wt.%的电弧增材制造TC4钛合金经过HVC氢处理后组织的演变规律。结论表明,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集束变的更加细小,且有氢化物的产生。随后在810℃温度下对置氢钛合金进行淬火,组织中生成了α′ 、α″和亚稳相βM。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。

Abstract:

This paper studies the evolution of the microstructure of the wire arc additive manufactured TC4 titanium alloy with a hydrogen content of 0.55wt.% after HVC hydrogen treatment. The conclusion shows 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 lamellar α clusters. 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 a temperature of 810℃, and α′, α″ and metastable phase βM were formed in the structure. In the process of aging and hydrogen removal, with the decomposition of martensite, metastable phase and hydride, the lamellar α grains in the columnar β crystals are significantly refined, forming a staggered fine needle-like microstructure.