Revisiting quantum effects on dislocation glide in bcc metals from DFT calculations and machine-learning potentials
ASNR/PSN-RES/SEMIA/LSMA Centre d’études de Cadarache（法国原子能和替代能源委员会卡达拉舍研究中心）；Université Paris-Saclay, CEA, Service de recherche en Corrosion et Comportement des Matériaux, SRMP（巴黎萨克雷大学，法国原子能和替代能源委员会材料腐蚀与行为研究服务处）；Univ. Lyon, UCBL, Institut Lumière Matière, UMR CNRS 5306（里昂大学，里昂第一大学，光物质研究所）
Arnaud Allera, Lisa Ventelon, Mihai-Cosmin Marinica, David Rodney, Laurent Proville
Quantum zero-point effects have been long proposed to explain a well-known discrepancy between the low-temperature flow stresses of body-centered cubic metals and corresponding atomistic models of plastic flow. Previous investigations on quantum effects relied on empirical interatomic potentials, which poorly reproduce dislocation energy landscapes compared to density functional theory (DFT) calculations. Here, we revisit this problem using DFT and machine-learning interatomic potentials (MLIPs). We show that while quantum effects do contribute to dislocation glide at low temperature, their magnitude is much lower than previously reported, and insufficient to reconcile atomistic predictions with experiments. Our results thus reopen a long-standing question and challenge for predictive atomistic modeling, on a fundamental property of crystals.
Electronic Selection Rules Controlling Dislocation Glide in bcc Metals
最近的{ \it ab initio}密度泛函理论对Mo和Ta中孤立螺位错的研究，使体心立方金属变形行为的结构-性能关系的有效性受到质疑。这些现有的关系是半经典的性质，从原子的研究V族和VI族过渡金属的变形性能。我们发现，这些结构-性能关系的正确形式是完全量子力学的，涉及耦合的电子状态与应变场的长$a/2<111>$螺旋位错的核心。
Which stresses affect the glide of screw dislocations in bcc metals?
在分子静力学计算中，通过直接应用应力，我们确定了影响体心立方钨中1/2螺旋位错滑移的应力分量<111>。这些结果表明，静水应力和平行于位错线的正应力对位错滑移不起作用。因此，位错的Peierls应力不能像Koester A，Ma A，Hartmaier A. Acta Mater 2012; 60：3894，而是它们的组合在垂直于位错线的平面中引起等双轴拉伸-压缩（并因此剪切）。1/2螺旋位错的Peierls应力<111>则仅取决于平行于Burgers矢量的剪应力所施加的平面的取向以及垂直于滑移方向的剪应力的大小和取向。
Multiscale modeling of plastic deformation of molybdenum and tungsten: I. Atomistic studies of the core structure and glide of 1/2<111> screw dislocations at 0 K
