对Ti55531合金棒材和锻件进行不同工艺的固溶和时效热处理，研究了热处理工艺对其显微组织和拉伸性能的影响。结果表明：随着固溶温度升高(575～650 ℃)，棒材中的初生α相由颗粒状变为条状或短棒状，直至全部变为β晶粒，室温抗拉强度和屈服强度明显增大，伸长率和断面收缩率大幅下降;随着时效温度降低，短棒状或条状α相逐渐溶解并球化析出α颗粒，室温抗拉强度和屈服强度明显增大，伸长率和断面收缩率显著降低;为使钛合金棒材的室温强度和塑性达到最佳匹配，固溶温度应控制在相变点以下，时效温度宜选择在600~620 ℃区间;固溶温度在相变点以下，时效温度为600 ℃时，锻件的强度和塑性可满足相关标准的要求。

Heat treatement processes with different solid-solution and aging temperatures were carried on Ti55531 titanium alloy bar and forging,and the effects of heat treatment processes on microstructure and tensile properties were studied. Results show that, with the increase of solid-solution temperature from 575 ℃ to 650 ℃, primary α phase in bar changed from granulated shape to strip or short bar-like, and until to change to β grains. The tensile strength and yield strength at room temperature obviously increased, the elongation and reduction of area dropped sharply with the increase of solid-solution temperature. With the decrease of aging temperature, the strip or short bar-like α phase gradually dissolved and precipitated with granulated shape, and tensile strength and yield strength at room temperature obviously increased and elongation and reduction of area sharply decreased. In order to obtain a best match between strength and plasticity for the bar, the solid-solution temperature should below the phase transition point and aging temperature within the range of 600 ℃ to 620 ℃. Strength and plasticity of the forging could meet the requiements of relavant standard when the solid solution temperature was below phase transition point and aging temperature was 600 ℃.