紧固件用TC16钛合金强化热处理工艺研究

Study of Heat Treatment Process on TC16 Titanium Alloy for Fastener

利用光学显微镜、扫描电镜以及拉伸实验机,研究不同热处理工艺下TC16钛合金的显微组织及力学性能。结果表明：退火后的组织为等轴α＋β,晶粒大小约为1μm;固溶处理的组织为初生α＋α＂＋亚稳β,随着固溶温度的升高,初生α相减少,抗拉强度不随固溶温度的变化而变化,屈服强度较退火态下降较大,屈强比仅为0.4~0.47;时效处理后的组织为初生α＋α＋β,α、β呈片状相间分布于原始β晶粒内,时效处理后的抗拉强度最高可达1226MPa,强塑积最高达21834MPa·%;退火态与固溶态的拉伸断口为韧性断口,而时效处理后的拉伸断口为准解理断口。

Microstructure and mechanical properties of TC16 titanium alloy for fastener are studied by OM, SEM, and tensile testing machine. The results show that equiaxed α and β grains are observed at annealing treatment, of which the size is about 1μm. There are primary α ＋α＂ ＋ metastable β phases after solution treatment. With the increase of solution temperature, the amount of primary α grains is decreased, tensile strength does not change at different solution temperatures, and the yield ratio is only 0.4~0.7. The primary α ＋ α ＋ β phases are observed at aging treatment, with lamellar α and β phase distributing in original β phase, and strength and product of strength and elongation are up to 1226 MPa and 21834MPa·% after aging treatment. The tensile fracture is tough break after annealing and solution treatment, which is quasi-cleavage fracture after aging treatment.