热处理工艺对TA15钛合金棒材组织和性能的影响

Effect of Heat Treatment Process on Microstructure and Mechanical Properties of TA15 Titanium Alloy Bars

研究了普通退火、β退火的单重热处理制度和强韧化的双重热处理制度对TA15钛合金棒材组织和性能的影响规律。结果表明,在普通退火温度范围内,合金组织形貌变化不大,均为等轴组织,合金的强度和冲击韧性随退火温度的升高而增加,塑性基本保持不变;β退火得到粗大的魏氏体组织,综合力学性能最差;在双重热处理过程中,第二重热处理温度主要影响片层α相的厚度,随着第二重热处理温度的升高,片层α相厚度增加,合金的强度降低,冲击韧性增加。当热处理制度为975℃×1 h/WQ+850℃×2h/AC时,合金组织由约24%的初生等轴α相、55%左右的网篮α相和β转变组织组成,此时合金具有良好的强韧性匹配。

The effect of normal annealing heattreatment,β heat treatment and dual heat treatment process on microstructure and mechanical properties of TA15 titanium alloy bars was studied. The results indicate that the equiaxed microstrcuture can be acquired during normal annealing heat treatment. The strength and impact toughness of TA15 titanium alloy increase with the increasing of annealing temperature. Widmanstatten microstrcuture can be got after βheat treatmen and shows the lowest mechanical properties. The thickness of α phase plate is determined by the temperature of the second heat treatment during dual heat treatment process,as the temperature increases,the α phase plate thicken and impact toughness increases,while the strength decline. When the heat treatment process is 975 ℃ × 1 h/WQ ＋ 850 ℃ × 2 h/AC,the alloy has the best mechanical properties with about 24% equiaxed α and 55% α plates and transform β microstructure.