热处理工艺对Ti2AlNb合金棒材显微组织和性能的影响

Effects of Heat Treatment on Microstructure and Mechanical Properties of TiAlNb Alloy Bar

采用光学显微镜、扫描电镜及万能试验机研究了不同热处理工艺对Ti2AlNb合金显微组织及室温、高温力学性能的影响。结果表明,该合金经980℃退火处理后,针状O相演变成片层状O相,等轴α2相边缘的RimO相析出增多,显微组织为B2基体+等轴α2+等轴O相+片层状O相+RimO相组织。相比锻态和不同固溶时效态试样,980℃退火试样的室温与650℃高温的力学性能匹配最好,抗拉强度分别为1005、780MPa,断后伸长率分别为6.6%、8.9%,断面收缩率分别为9.3%、10.8%。

The effects of different heat treatment processes on the microstructure and mechanical properties of Ti2AlNb alloy at room temperature and high temperature were studied by optical microscope, scanning electron microscope and universal testing machine. The results show that the needle O phase evolves into lamellar O phase after 980 ℃ annealing. The Rim O phase segregation of equiaxed α2 phase edge increases, and the microstructure is B2 matrix, equiaxed α2, equiaxed O photo and layered phase structure. Compared with forging and solid solution, the mechanical properties of 980℃ annealed samples at room temperature and 650 ℃ at high temperature are best matched, with the tensile strength of 1005 MPa and 780 MPa, the elongation at break of 6.6% and 8.9%, the section shrinkage of 9.3% and 10.8%, respectively.