TiAl合金PST晶体高温蠕变特性及蠕变失稳机制

COMPRESSION CREEP BEHAVIOR AND INSTABILITY MECHANISM OF TiAl PST CRYSTALS AT HIGH TEMPERATURE

对三种取向的TiAl合金PST晶体在800℃条件下的压缩蠕变曲线进行了测试，并对其蠕变失稳机制进行了研究．研究结果表明，PST晶体的蠕变性能强烈地取决于片层界面与外力轴的夹角；三种取向的PST晶体试样在蠕变第三阶段表现出不同的蠕变失稳方式；对于＝90°的试样，在本蠕变条件下过早地出现蠕变第三阶段，这与该取向试样α2片层在蠕变过程中发生球化以及剪切带的产生有关．

The compression creep behavior and creep instability of TiAl PST crystals with three orientations at 800℃ were investigated. The results indicated that the creep resistance of PST crystals is strongly dependent on the anglebetween the lamellar boundaries and loading axis. The creep instability is identified to occur in different ways in the samples with the three orientations. For samples with =90°, the creep instability is associated with the spheroidization of α2 and the formation of the shear band during the creep, it may account for the early onset of the tertiary creep in these oriented samples.