等温锻造过程中变形量对TiB_(w)/Ti60复合材料显微组织和力学性能演变的影响

Effect of deformation degree on microstructure and mechanical properties evolution of TiB_(w)/Ti60 composites during isothermal forging

为了研究TiB晶须增强Ti60复合材料在热压缩过程中变形程度对微观结构和力学性能的影响,在1030℃,应变速率为1×10^(-2)s^(-1),变形量为30%、50%和70%的条件下分别进行等温锻造。研究结果表明,随着应变的增加,大角度晶界(HAGBs)的比例在70%变形量时显著上升到71.47%。由于材料再结晶效率的提高,α_(s)晶粒的织构成分逐渐成为主导织构成分。TiB能够促进再结晶晶粒的形核并且阻碍晶粒长大。经过等温锻造,复合材料在室温和600℃下的力学性能均有所提高,在50%变形量时锻造试样具有最佳的拉伸强度和伸长率。在拉伸试验过程中TiB晶须承受周围基体传递的载荷,从而材料表现出强化效果。

In order to investigate the influence of deformation degree on microstructure and mechanical properties during hot compression,TiB whiskers reinforced Ti60 composites were subjected to isothermal forging at 1030℃and strain rate of 1×10^(−2) s^(−1) under 30%,50%,and 70%deformation degrees.The results showed that with strain increasing,the fraction of high angle grain boundaries(HAGBs)significantly increased to 71.47%at 70%deformation degree,and the texture components ofαs colonies gradually became dominant due to the enhanced recrystallization efficiency.TiB can promote nucleation of recrystallized grains and impede grain growth.After isothermal forging,the mechanical properties of composites at both RT and 600℃ were improved,and the specimen compressed at 50%deformation degree showed the best tensile strength and elongation.During tensile tests,the TiB whiskers can bear the load transmitted from surrounding matrix,showing strengthening effect on the material.