激光增材制造Ti_2AlNb基合金的组织与性能

Microstructure and properties of laser additive manufacturing Ti_2AlNb-based alloy

利用激光增材制造技术,分别在扫描速率为3、4、5 mm/s的条件下制备出Ti-22Al-25Nb合金薄壁试样,分析了3组试样的相组成、显微组织和力学性能。结果表明,激光增材制造Ti-22Al-25Nb合金显微组织由B2、O和α2相组成,随着扫描速率的增加,合金析出相体积分数和基体B2相平均晶粒尺寸呈现出减小趋势,合金室温、高温抗拉强度逐渐升高。扫描速率为5 mm/s时,所沉积材料的室温和750℃高温的抗拉强度最高,分别为1053 MPa和665 MPa;析出相体积分数和B2相平均晶粒尺寸最小,分别为72.52%和156μm。

The thin-wall samples of Ti-22Al-25 Nb alloy were prepared through the laser additive manufacturing process under laser scanning velocities of 3,4 and 5 mm / s respectively. The phase constitution,microstructure and mechanical properties for the three sample groups were investigated. The results show that the laser additive manufacturing Ti-22Al-25 Nb alloy is composed of B2,O and α2phases. With the increase of the scanning velocity,the volume fraction of precipitated phase and the average grain size of B2 phase decrease,while the tensile strength increases at room temperature and high temperature. For deposited alloy under laser scanning velocity of 5 mm / s,the tensile strength under room temperature and 750 ℃ are 1053 MPa and 665 MPa respectively,the volume fraction of precipitated phase and the average grain size of B2 phase are also as low as 72. 52% and 156 μm.