采用磨削和抛光作为最后工序制备了铸造TiAl合金的标准拉伸试样, 对比分析了两种试样的表面质量和表面残余应力,并进行了室温拉伸试验。结果表明: 经磨削和抛光后TiAl合金表面的显微组织与其铸态的相同, 均为近层片状组织; 抛光使试样表面粗糙度由磨削后的0.51 μm降至0.22 μm, 磨痕数量减少, 磨痕由锐角变为钝角; 两种试样表面均为残余压应力状态, 但抛光表面的残余压应力较高; 抛光后试样的室温伸长率明显提高, 由磨削后的1.33%增至2.33%。

The standard tensile specimens of as-cast titanium aluminide alloy were prepared by using grinding and polishing as the final procedure. The surface quality and surface residual stress of the two specimens were comparatively analyzed. Tensile tests were taken at room temperature. The results show that the surface microstructure of the ground and polishing TiAl alloy was the same as that of the as-cast alloy, which was near lamellar microstructure. It decreased the surface roughness of the ground specimen from 0.5 μm to 0.22 μm by polishing. The wear scar guantity decreased, and its angle changed from acute angle to obtuse angle. The surface stress of both the two specimens was compressive residual stress, while that of the polished specimen was higher. The elongation at room temperature of the polished specimens was improved obviously, which was increased from 133% to 2.33%.