Multi-scale investigation of short-range order and dislocation glide in MoNbTi and TaNbTi multi-principal element alloys
Multi-scale investigation of short-range order and dislocation glide in MoNbTi and TaNbTi multi-principal element alloys
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DOI：
10.1038/s41524-023-01046-z
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发表时间：
2022-03
影响因子：
9.7
通讯作者：
Huijin Zheng;Lauren T. W. Fey;Xiang-Guo Li;Yong-Jie Hu;L. Qi;Chi Chen;Shuozhi Xu;I. Beyerlein;S. Ong
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文献类型：
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作者：
Huijin Zheng;Lauren T. W. Fey;Xiang-Guo Li;Yong-Jie Hu;L. Qi;Chi Chen;Shuozhi Xu;I. Beyerlein;S. Ong
耐火多主元合金(RMPEA)是一种很有前途的高温结构材料。在这里，我们用多尺度模拟方法研究了短程有序(SRO)对MoNbTi和TaNbTiRMPEA中位错滑移的影响。用矩张量势进行的蒙特卡罗/分子动力学模拟表明，MoNbTi的SRO程度远大于TaNbTi，局域成分对不稳定层错能有直接影响。从介观相场位错动力学模拟中我们发现，随着SRO的增加，位错滑动所需的平均USFE和应力也随之增加。由于随机成分波动引起的钉扎和脱钉，滑移位错经历了显著的硬化，较高的SRO降低了USFE的弥散程度，从而降低了硬化量。最后，我们展示了外加应力对扩展位错环的形态的影响。
Refractory multi-principal element alloys (RMPEAs) are promising materials for high-temperature structural applications. Here, we investigate the role of short-range ordering (SRO) on dislocation glide in the MoNbTi and TaNbTi RMPEAs using a multi-scale modeling approach. Monte carlo/molecular dynamics simulations with a moment tensor potential show that MoNbTi exhibits a much greater degree of SRO than TaNbTi and the local composition has a direct effect on the unstable stacking fault energies (USFEs). From mesoscale phase-field dislocation dynamics simulations, we find that increasing SRO leads to higher mean USFEs and stress required for dislocation glide. The gliding dislocations experience significant hardening due to pinning and depinning caused by random compositional fluctuations, with higher SRO decreasing the degree of USFE dispersion and hence, amount of hardening. Finally, we show how the morphology of an expanding dislocation loop is affected by the applied stress.