热加工工艺对挤压态FGH4096合金临界晶粒长大的影响

基于挤压态FGH4096合金双圆锥台试样热压缩变形及过固溶热处理试验,结合DEFORM有限元软件数值模拟,确定试样中各等效应变范围内临界晶粒长大分布规律,研究热加工工艺对挤压态FGH4096合金临界晶粒长大的影响。结果表明:在温度980~1060℃、应变速率0.003~0.03 s^−1条件下,双圆锥台试样热变形后再经过固溶热处理,合金临界晶粒长大的窗口条件从低温低应变速率向高温高应变速率转变,其中(980℃、0.03 s^−1)、(1060℃、0.003 s^−1)条件下可以避免出现临界晶粒长大,并获得均匀晶粒组织。当变形温度为980℃时,随着应变速率的增加,异常晶粒长大程度减小,且合金临界晶粒长大位置的临界等效应变数值降低;当应变速率为0.03 s^−1时,随着变形温度的升高,异常晶粒长大程度增大,且试样发生临界晶粒长大的等效应变区域扩大。

Design for Isothermal Forging of Ti-46.5Al-2.5V-1.0Cr-0.3Ni Alloy

The three-dimensional finite element method was utilized to investigate the isothermal forging of Ti-46.5Al-2.5V-1.0Cr-0.3Ni（atomic percent,%）alloy.The partition of height reduction,effective strain,and damage of the alloy during the forging were analyzed.The simulation results were verified by experiments.The results show that large plastic deformation can improve the homogeneity of the deformed microstructure and the higher accumulative height reduction can be achieved through two-step forging.With the isothermal forging of two-step reduction of 60%＋62.5%（total height reduction of 85%）,the entire forged pancake can acquire refined microstructure and expand the uniform flow zone to almost the entire volume.