The primary and steady-state compressive creep deformation behavior of an as-cast high Nb containing γ-TiA1 alloy having remnant β(B2)-phase has been studied over the temperature range of 750–850 °C at constant initial applied stress levels between 75-200 MPa. The creep curves derived over the entire creep testing conditions show a prominent primary creep regime which is attributed to the presence of dislocation debris of the coarse γ-grains at the colony boundaries. The stress and temperature dependence of the steady-state creep rate follows the Norton-Bailey power law and the corresponding average value of the stress exponent and apparent activation energy are estimated to be 3.6 and 375 kJ/mol, respectively. The average value of the stress exponent in conjunction with the dislocation substructure of the crept samples suggests that the kinetics of creep deformation within the studied experimental conditions is controlled by the non-conservative motion (climb) of dislocations. Further misorientation analyses of the phase-resolved EBSD maps imply that for most of the conditions creep strain is carried by the γ-TiAl phase. Consequently, contrary to the commonly believed idea, the β(B2)-phase does not appear to deteriorate the creep resistance of the present alloy below suitable combinations of temperature and stress. Beyond these conditions, the concurrent deformation of γ-TiAl and β(B2)-phases is found to enhance the steady-state creep rate. In addition, characteristics of the dynamic transformation of β(B2) phase into γ and α₂ phases during creep and its effect on the steady-state creep rate are further considered. Finally, the application potential of the present alloy is compared through a composite plot of Larson-Miller parameter with several other potential alloys reported in the literature.

研究了在750-850°C的温度范围内，恒定的初始施加应力水平下，在750-850°C的温度范围内研究了铸态的高Nb含残余β（B2）相的含γ-TiA1合金铸态的稳态压缩蠕变变形行为。 75-200兆帕。在整个蠕变测试条件下得出的蠕变曲线显示出突出的主要蠕变状态，这归因于在集落边界处存在粗大γ晶粒的位错碎片。稳态蠕变速率的应力和温度相关性遵循Norton-Bailey幂律，并且应力指数和视在活化能的相应平均值分别估计为3.6和375 kJ / mol。应力指数的平均值与蠕变样品的位错亚结构相结合，表明在研究的实验条件下蠕变变形的动力学受位错的非保守运动（爬升）控制。相分辨的EBSD图的进一步取向错误分析表明，在大多数情况下，蠕变应变由γ-TiAl相承担。因此，与通常认为的观点相反，在适当的温度和应力组合下，β（B2）相似乎不会使本合金的抗蠕变性变差。除这些条件外，还发现γ-TiAl和β（B2）相的同时变形会提高稳态蠕变速率。此外，β（B2）相动态转变为γ和α的特征 相分辨的EBSD图的进一步取向错误分析表明，在大多数情况下，蠕变应变由γ-TiAl相承担。因此，与通常认为的观点相反，在适当的温度和应力组合下，β（B2）相似乎不会使本合金的抗蠕变性变差。除这些条件外，还发现γ-TiAl和β（B2）相的同时变形会提高稳态蠕变速率。此外，β（B2）相动态转变为γ和α的特征 相分辨的EBSD图的进一步取向错误分析表明，在大多数情况下，蠕变应变由γ-TiAl相承担。因此，与通常认为的观点相反，在适当的温度和应力组合下，β（B2）相似乎不会使本合金的抗蠕变性变差。除这些条件外，还发现γ-TiAl和β（B2）相的同时变形会提高稳态蠕变速率。此外，β（B2）相动态转变为γ和α的特征 发现γ-TiAl和β（B2）相的同时变形可提高稳态蠕变速率。此外，β（B2）相动态转变为γ和α的特征 发现γ-TiAl和β（B2）相的同时变形可提高稳态蠕变速率。此外，β（B2）相动态转变为γ和α的特征进一步考虑了蠕变过程中的_两个阶段及其对稳态蠕变速率的影响。最后，通过Larson-Miller参数与文献中报道的其他几种潜在合金的合成图对本合金的应用潜力进行了比较。