(1. 北京有色金属研究总院 有色金属材料制备与加工国家重点实验室，北京 100088；
2. 宝钛集团有限公司，宝鸡 721014)
摘 要: 采用光学显微镜、室温和高温拉伸实验研究热处理对BTi-6431S合金板材微观组织和力学性能的影响。结果表明：升高第一阶段的退火温度，块状初生α相粗化，趋于等轴状，体积分数逐渐降低。β相和次生α相的体积分数增加。室温强度和塑性变化不大。高温强度随第一级退火温度的升高而逐渐上升，塑性下降。在相同第一阶段退火温度下，第二阶段退火温度的升高使得初生α相含量急剧增加，趋于板条状，β转变组织含量降低，室温和高温拉伸性能同时下降。通过合理的控制双重退火的温度，可使BTi-6431S合金具有良好的高温强度和室温塑性的匹配。
关键字: BTi-6431S合金板材；双重退火；退火温度；显微组织；力学性能
（1. State Key Laboratory of Nonferrous Metals and Processes,
General Research Institute for Nonferrous Metals, Beijing 100088, China;
2. Baoti Group Co., Ltd., Baoji 721014, China）
Abstract:The influence of variant heat treatment processing (double annealing) on the microstructure and mechanical properties of the BTi-6431S plate were investigated by optical microscope and tensile tests at room and elevated temperatures. The results show that, with the first stage annealing temperature increasing, the shape of primary α phase (αp) becomes coarse, changes into equiaxial, and its volume fraction decreases gradually, while the volume fractions of β-matrix (βt) and secondary α phase increase. The room temperature strength and ductility have not obvious variation, but the high temperature strength increases and the ductility decreases. However, after the first annealing at the same temperature, increasing secondary aging temperature promotes αp transforming into lath-shape, meanwhile reducing the volume fraction of βt, resulting in the mechanical properties decreasing. The best alloy microstructure with good high temperature strength and room temperature plasticity can be obtained by choosing double annealing temperature parameter reasonably.
Key words: BTi-6431S plate; double annealing; annealing temperature; microstructure; mechanical properties
