研究了热处理对高强Zr₄₇Ti₄₅Al₅V₃ (质量分数, %)合金微观组织和力学性能的影响. 结果表明, 该合金初始加工态由α (hcp)和β (bcc) 2相组成, 板条状的α相均匀分布在β相基体上. 合金虽然具有很高的强度, 但塑性很小, 其抗拉强度为1648 MPa, 而其延伸率只有0.8%. DSC结果表明, 合金在560~750 ℃之间有α→β的相转变. 对热处理后样品的力学性能检测结果表明, 合金中β相含量的增多, 使其塑性提高, 但强度有所降低; 通过在α→β相变点上不同温度的退火处理, 调控α与β相的相对含量可以获得强度和塑性的良好配合. 当合金中β相的体积分数为60%左右时, 合金具有较佳综合力学性能, 其抗拉强度为1398 MPa, 延伸率达到3.1%.

Due to the high stress, relative low density and excellent resistance of radiation, Zr-based alloys have become promising structural materials used in the space environment. The relationship between microstructure and mechanical properties is the key issue for designing Zr-based alloy in different alloy systems and has attracted extensive research interests. The microstructures could be adjusted by different processes of heat treatment and thus realizing the optimization of mechanical properties. In this work, the initial microstructure and mechanical properties of a high strength Zr₄₇Ti₄₅Al₅V₃ (mass fraction, %) alloy was investigated. The XRD results reveal that the initial Zr-based alloy is consisted of α (hcp) and β (bcc) phases. Transmission electron microscopy result shows that the lathy α phase homogenously distributed within the β phase matrix. Mechanical tests of this alloy show very high strength but limited plasticity. The tensile strength is 1648 MPa. However, the tensile elongation is only 0.8%. DSC trace indicates that the transition temperature of α phase to β phase is located between 560~750 ℃ that provides the possibility to adjust the microstructures through different processes of heat treatment. In order to optimize the mechanical properties, several different processes of heat treatment were conducted on this Zr-based alloy, and the relative volume fraction of α and β phase is successfully adjusted. According to the mechanical tests, the plasticity becomes larger as the amount of β phase increases with a slight decrease in strength. When the volume fraction of β phase is about 60%, the alloy exhibits the optimal mechanical performance with a tensile strength of 1398 MPa and an elongation of 3.1%.