【摘要】 研究了Ti-22Al-25Nb合金在α2+B2相区等温锻造及不同制度热处理,其显微组织演变规律和室温、高温拉伸性能变化。结果表明:在α2+B2相区等温锻造后显微组织仍由等轴α2相颗粒、O相包裹着的等轴α2相、细小板条状O相与B2基体组成,与原始锻棒组织的区别在于等轴α2相颗粒发生溶解,数量减少,尺寸下降;等温锻造后再在O+B2相区固溶处理的,组织中等轴α2相颗粒分解,由等轴α2/O相颗粒、板条O相和B2基体组成,且随固溶温度升高,板条O相溶解,变粗、变短;等温锻造后经固溶加时效处理时,B2基体中析出二次针状O相,且随时效温度升高,二次针状O相变粗、变短,室温及650℃高温拉伸性能也随时效温度升高,表现为强度降低而塑性提高。更多还原

【Abstract】 The microstructure evolution and tensile properties at room and high temperature of Ti-22 Al-25 Nb alloy after isothermal forging in α₂+ B2 phase region and different heat treatments were investigated. The results show that the microstructure is still composed of equiaxed α₂ phase grains,equiaxed α₂ phase surrounded by O phase,fine slab O phase and B2 matrix after isothermal forging in α2+ B2 phase zone. And the difference is that the equiaxed α₂ phase particles dissolve,the number and the size decrease. After the isothermal forging and solid solution treatment in the O+ B2 phase zone,the equiaxed α₂ phase particles in the microstructure are decomposed and the microstructure consists of axis α₂/O particles,slab O phase and B2 matrix. With the increase of solution temperature,the slab O phase dissolves and becomes thicker and shorter. After isothermal forging + solution treatment + aging treatment,the secondary acicular O phase is precipitated from the B2 matrix,and as the aging temperature increases,the secondary acicular O phase becomes thicker and shorter,and the tensile properties at room temperature and 650 ℃ also increase with the aging temperature,showing the decrease of strength and improvement of plasticity.更多还原