【摘要】 研究了Ti-22Al-25Nb合金等轴组织的演变及其对拉伸性能的影响。结果发现,经α₂+O+B2三相区等温锻后,在O+B2两相区固溶过程中,组织中初始O相板条粗化变短,冷却析出的细板条则溶解到B2基体中,α₂/O相颗粒不发生明显变化,固溶温度升高使得少量等轴O相发生溶解,rim O相厚度减小。而在O+B2两相区时效的过程中,大量细密的二次O相板条从B2基体析出,少量被rim O包围的α₂相向O相转变。时效温度升高时,析出的二次板条O相变得粗大,总体含量减少,rim O厚度增加。时效温度的升高还使得合金强度下降而塑性增加。更多还原

【Abstract】 The equiaxed microstructure evolution and its effect on the tensile properties of Ti-22Al-25Nb alloy were studied.Results show that during the solution in O+B2 phase region,the primary lath O phase in microstructures obtained in isothermal forging inα₂+O+B2phase region is coarsened and becomes shorter and fine lath O dissolves into B2 matrix phase,while equiaxedα₂/O phase does not change significantly.A part of equiaxed O phase dissolves and rim O phase becomes thinner at higher solution temperatures.During the aging in O+B2 phase region,lots of secondary fine lath O phase precipitate from B2 phase,and a littleα₂ phase surrounded by rim O transforms to O phase.Higher aging temperatures result in coaser but less secondary lath O phase and thicker rim O phase,as well as lower tensile strength and higher ductility.更多还原