固溶态Ti-41Nb合金的微观组织与力学行为研究

Study on Microstructure and Mechanical Behavior of Solution treated Ti-41Nb Alloy

摘要:

采用光学显微镜、力学性能测试和原位同步辐射高能X射线衍射等方法系统地研究了固溶态Ti-41Nb合金的微观组织与力学行为。研究结果表明，Ti-41Nb合金经800℃固溶淬火处理后，其等轴β基体上分布着微量的板条状α″马氏体，呈现典型的双相结构。在拉伸过程中，固溶态Ti-41Nb合金除发生弹性变形外，还发生了β→α″应力诱发马氏体相变。应力诱发马氏体相变在0.0-3.3%应变范围内较剧烈，在3.3-4.0%应变范围内相对轻微。在随后的卸载过程中，固溶态Ti-41Nb合金发生了弹性回复，同时伴随着α″→β逆马氏体相变。卸载后，固溶态Ti-41Nb合金中仍有大量的α″马氏体未转变为β母相，这导致合金仍有2.9%的残余应变。

Abstract:

The microstructure and mechanical behavior of solution treated Ti-41Nb alloy were systematically investigated by optical microscope, tensile test and in situ synchrotron high-energy X-ray diffraction. After solution treated at 800℃ plus water quenching, Ti-41Nb alloy presents a typical dual-phase structure which is characterized by exiguous lath-shaped α" martensite distributed on the equiaxed β matrix. The stress induced martensitic transformation (SIMT), together with elastic deformation, takes place concurrently during loading. The stress-induced martensitic transformation from β to α″ takes place intensively in the strain range from 0.0% to 3.3% but slightly from 3.3% to 4.0%. In the subsequent unloading process, the solution treated Ti-41Nb alloy undergoes elastic recovery, accompanied by the reverse martensitic transformation from α″ to β. After unloading, a large amount of α″ martensite has not been transformed into β parent phase, which results in a residual strain of 2.9%.