热处理工艺对Ti55531合金组织与性能的影响

Effect of Different Heat Treatment Process on Microstructure and Mechanical Properties of Ti55531 Alloy

采用正交试验研究不同热处理工艺对Ti55531合金显微组织和力学性能的影响。结果表明,显著影响合金显微组织和力学性能的因素依次是固溶温度、时效温度、时效时间。随固溶温度的升高,初生α相含量明显减少,α相的等轴性表现较好且分布更加均匀,抗拉强度逐渐增加,伸长率下降;随时效温度的升高,次生α相开始增加、长大,组织向双态组织转变,使得抗拉强度下降,伸长率增加。其合理的"固溶+时效"热处理工艺为"820℃×2h固溶,空冷+580℃×10h时效,空冷",抗拉强度为1 370MPa,伸长率为8.5%。

Abstract：Influences of different heat treatment process on mechanical properties and microstructures of the Ti55531 titanium alloy were investigated by the orthogonal testing with three factors to three level. The results reveal that the influencing orders on microstructure and mechanical properties of the alloy are presented as follows- solid solution temperature, ageing temperature and ageing time. With increas- ing in solid solution temperature, primary phase is decreased greatly with desirable equaixed feature and uniform distribution, meanwhile, tensile strength is increased with decreasing in elongation. With the increase of ageing temperature, sub-α phase is increased and grown, and microstructure is transformed into dual-phase structure, resulting in the decrease of tensile strength and the increase of elongation. With solid solution treatment at 820 ℃ for 10 h and air cooling, and then aging at 580 ℃ for 10 h and air cooling, the tensile strength and elongation of the Ti alloy reach 1 370 MPa and 8.5 %, respectively.