热处理工艺对TC4-DT钛合金厚板组织和性能的影响

Effects of heat treatment process on microstructure and mechanical properties of TC4-DT titanium alloy plate

研究了不同热处理制度对TC4-DT合金厚板显微组织和力学性能的影响。结果表明,TC4-DT合金在α+β两相区固溶处理时,随着固溶温度的降低,初生α相含量逐渐增多,强度降低,塑性增加;固溶冷却速率越慢,获得的α'马氏体越少,随后的时效强化效果越小。随着时效温度的提高及时效时间的延长,析出的次生α相数量增多,晶粒粗化,屈服强度出现先增加后下降趋势,塑性变化不大。因此,最佳热处理工艺为955℃×1 h,AC+550℃×8 h,AC,经该工艺处理的试样综合力学性能较好。

Effects of heat treatment on microstructure and mechanical properties of TCA-DT titanium alloy plate were investigated. The results show that the primary α-phase increases, strength decreases and ductility increases with the solution temperature decreasing when the TCA-DT alloy is heated in the α＋β phase region. Moreover, the slower the cooling rate, the less α＇ phase will be acquired and the hardening effect will be decreased. With the aging temperature and aging time increasing, the amount of precipitated secondary α phase increases and grain coarsens, the yield strength increases first and then decreases, but the ductility changes a little. Therefore, the best heat treatment process of TC4-DT alloy may be 955 ℃ × 1 h, AC ＋ 550 ℃ × 8 h, AC, under which the alloy will get excellent comprehensive mechanical properties.