In this study, γ-TiAl-based alloy with chemical composition of Ti–45Al–5Nb (in at.-%) fabricated by powder metallurgy method was crept at 700°C under 200–500 MPa. The creep properties and the microstructure after creep tests were investigated. The results showed that the γ-TiAl-based alloy was composed of equiaxed γ-TiAl grains and α 2-Ti3Al grains with average sizes of 1.4 and 0.5 μm, respectively. The creep resistance deteriorated generally with increased applied stresses. The typical intergranular fracture characteristics were observed though the grains were small. The calculated stress exponent and activation energy revealed the main creep mechanism of grain boundary sliding. Furthermore, twinning and dynamic recrystallisation also led to the creep deformation.

中文翻译：

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粉末冶金制备等轴细晶γ-TiAl基合金的蠕变行为

在这项研究中，化学成分为 Ti-45Al-5Nb（at.-%）的γ-TiAl 基合金通过粉末冶金方法在 700°C 和 200-500 MPa 下蠕变。研究了蠕变试验后的蠕变性能和微观结构。结果表明，γ-TiAl基合金由等轴γ-TiAl晶粒和α2-Ti3Al晶粒组成，平均尺寸分​​别为1.4和0.5μm。抗蠕变性通常随着施加应力的增加而恶化。尽管晶粒很小，但观察到了典型的沿晶断裂特征。计算的应力指数和活化能揭示了晶界滑动的主要蠕变机制。此外，孪生和动态再结晶也导致蠕变变形。