热工艺参数对TA15钛合金片状α相静态球化行为的影响

Effect of thermal processing parameters on static globularization behaviour of lamellarαphase of TA15 titanium alloy

通过等温恒应变速率压缩试验及后续不同条件的静态热处理,研究了预应变、热处理温度及热处理时长工艺参数对TA15钛合金片状α相静态球化行为的影响,并分析了其内在球化机制。结果表明,最终球化效果随预应变的增大而变好,不同预应变下静态球化的参与比例和作用模式不同。在两相区高温段850~950℃,球化行为对热处理温度敏感,球化分数随热处理温度升高而迅速增加;随着热处理时间的延长,球化分数和平均长宽比先迅速变化后平稳,两阶段分界点在0.2~0.5 h之间;α相的晶粒数量及平均晶粒尺寸随热处理时间的变化规律表明,TA15钛合金片状α相的静态球化通过晶界分离和组织粗化两种方式进行。

Through isothermal constant strain rate compression tests and subsequent static annealing under different conditions,the effects of prestrain,annealing temperature and annealing time on the static globularization behaviour of lamellarαphase of TA15 titanium alloy were studied,and the internal globularization mechanism was analyzed.The results show that the final globularization effect becomes better with the increase of prestrain,the proportion and the action mode of static globularization with different prestrain are different.At 850-950℃in the high temperature two-phase region,the globularization behaviour is sensitive to annealing temperature,and the globularization fraction increases rapidly with the increase of annealing temperature.With the extension of annealing time,the globularization fraction and average aspect ratio change rapidly at first and then steadily,the dividing point of the two stages is between 0.2-0.5 h.The variation of the grain number and average grain size ofαphase with annealing time shows that the static globularization of lamellarαphase of TA15 titanium alloy takes place through boundary splitting and microstructure coarsening.