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分析了热暴露温度、时间对TiAl合金表面完整性及室温拉伸性能的影响。结果表明,热暴露温度为700℃时,热暴露后试样表面残余压应力有所降低,温度升高至750和800℃时,试样表面残余压应力变化不大。经750和800℃热暴露后,试样表面生成厚度均匀的多重表面层;观察热暴露后试样断口可以观察到沿表面层和基体界面的连续裂纹和表层剥落;随着热暴露温度升高,表面层厚度显著增大,多重表面层明显并伴有层间裂纹。这些表面变化导致材料的室温抗拉强度降低,塑性明显降低。
The effects of heat exposure temperature and time on the surface integrity and room temperature tensile properties of TiAl alloy were analyzed. The results show that when the thermal exposure temperature is 700 ℃, the residual compressive stress on the surface of the specimen after thermal exposure is reduced. When the temperature is increased to 750 and 800 ℃, the residual compressive stress on the specimen surface does not change much. After thermal exposure at 750 and 800 ℃, multiple surface layers with uniform thickness were formed on the sample surface. The continuous cracks and surface spalling along the interface between the surface layer and the matrix were observed after the thermal exposure. After the thermal exposure temperature increased , The surface layer thickness increased significantly, multiple surface layer is obvious and accompanied by interlaminar cracks. These surface changes lead to a decrease in the tensile strength of the material at room temperature and a significant decrease in ductility.