摘要
研究Ti-5Al-5Mo-5V-1Cr-1Fe合金在β→α+β相变点以下热缩变形时的动态相变过程。发现在相变点以下0~100 K压缩时会促进应变诱导的α→β相变的发生。压缩过程中的形变储存能为相变提供驱动力。变形过程中位错和亚晶等缺陷增加,促进溶质元素的扩散,溶质元素的重新分布引起两相自由能的重新分布,促进α→β的转变。在{100}取向和{111}取向晶粒中还发现存在取向依赖特征,{111}取向晶粒中不充分的回复为相变提供更大的驱动力。另外,还研究了变形量和应变速率对相变的影响。
The dynamic phase transformation of Ti-5Al-5Mo-5V-1Cr-1Fe alloy during hot compression below the β transus temperature was investigated. Strain-induced α-to-β transformation is observed in the samples compressed at 0-100 K below the βtransus temperature. The deformation stored energy by compression provides a significant driving force for the α-to-β phase transformation. The re-distribution of the solute elements induced by defects during deformation promotes the occurrence of dynamic transformation. Orientation dependence for the α-to-β phase transformation promotion is observed between {100}-orientated grains and {111}-orientated grains. Incomplete recovery in {111}-orientated grains would create a large amount of diffusion channels,which is in favor of the α-to-β transformation. The effects of reduction ratio and strain rate on the dynamic phase transformation were also investigated.
引文
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