紧固件用TB2钛合金棒材热处理工艺研究

Study on Heat Treatment Processes of TB2 Titanium Alloy Bar for Fasteners

研究了热处理工艺对原始组织为粗大β晶粒+少量细小α晶粒的紧固件用TB2钛合金棒材组织与力学性能的影响。结果表明:随着固溶温度的升高,棒材组织中α相含量逐渐减少,β晶粒尺寸明显增大,经780℃固溶后强度和塑性匹配最好;固溶+时效处理时,随着时效温度的升高,棒材组织中析出的次生α相体积分数先增加后减少,且棒材强度先升高后降低;经固溶+预拉伸变形+时效处理后,棒材组织中晶粒有一定细化,次生片状α相含量增多,抗拉强度较固溶后直接时效提高了近10%。

The effect of heat treatment on the microstructure and properties of TB2 titanium alloy bar with coarse β grain and few fine α grain was studied.The results show that with the increase of solution temperature,the content of α phase decreases gradually,and the size of β grain increases obviously.After solution treatment at 780 ℃,the strength and plasticity of the bar match best.After solution+aging treatment,with the increase of aging temperature,the volume fraction of α phase increases first and then decreases,and the strength of the bar also increases first and then decreases.After solid solution+pre-stretching deformation+aging treatment,the grain is refined to a certain extent,the content of secondary flaky α phase increases,and the tensile strength of the bar is increased by nearly 10% compared with the direct aging after solid-solution.