仿生TiAl基合金的制备及力学性能

Fabrication and mechanical properties of bioinspired TiAl-based alloys

利用Ti-Al-TiC体系原位形成复合层,并对TC4钛合金箔(Ti6Al4V)机加工形成通孔结构,累积叠加后采用放电等离子烧结技术制备了通孔钛合金层/Ti 2AlC-TiAl基叠层复合板材。采用XRD、SEM、EBSD等测试手段分析相组成及微观结构,测量其室温力学性能,研究其强韧化及断裂机理。结果表明,加载方向与叠层结构方向垂直时,Ti 2AlC理论生成质量分数5%对应的复合板材的弯曲强度和断裂韧性分别达到665.87 MPa和24.83 MPa·m 1/2。通孔构型TC4钛合金强韧层设计实现了层与层之间的有效连接,改变了裂纹扩展路径。同时第二相Ti 2AlC对裂纹扩展也产生阻碍作用,从而提高了TiAl基叠层复合板材的综合力学性能。

TiAl-based laminated composite sheets were prepared by spark plasma sintering technology by overlapping of Ti-Al-TiC mixed powders and through-hole titanium alloy foils(Ti6 Al4 V). The phase composition and microstructure were analyzed by XRD, SEM, EBSD, and the room temperature mechanical properties were measured. The strengthening-toughening and fracture mechanism were investigated. The results indicate that the flexural strength and fracture toughness of the composite sheet with 5% Ti_(2)AlC have reached the maximum value of 665.87 MPa and 24.83 MPa·m^(1/2), respectively. The through-hole architecture design facilitates efficient layer-to-layer connections, and has changed the crack propagation path. The second phase of Ti_(2)AlC has exerted impact on the crack propagation, and improved the comprehensive mechanical properties of TiAl-based laminated composite sheets.