The Role of Dislocations in Melting Physics

This proposal will measure how crystal symmetry dictates the exotic non-classical dynamics of dislocations as crystals approach and reach Tm to build a data-inspired multiscale model for melting physics. Thus far, the details of bulk dislocation pathways to melting are based on advanced multiscale models, yet untested. Experiments have been unable to resolve the in-situ dynamics of how subsurface dislocations contribute to melting, limiting melt theory to model systems that over-simplify the physics. A new computational method predicted that just as the symmetry of the lattice destabilizes towards a disordered liquid, a plethora of defect interactions should create numerous degenerate pathways to melt. Our work on Al confirmed exotic multiscale dynamics for a single material. For robust comparison, we must generalize these trends. Our findings will reveal the key dislocation physics required to describe how defects at the mesoscale contribute to melting.

本研究提案旨在探明晶体趋近并达到熔点Tm时，晶体对称性如何支配位错的反常非经典动力学行为，以此构建面向熔化物理的数据驱动多尺度模型。迄今为止，体相位错通往熔化的路径细节仅依托先进多尺度模型提出，尚未经实验验证。现有实验无法解析次表层位错参与熔化过程的原位动力学机制，这使得现有熔化理论仅能应用于过度简化物理过程的模型体系。一项全新的计算方法预测，正如晶格对称性朝着无序液态发生失稳，大量缺陷间的相互作用将催生诸多通往熔化的简并路径。我们针对铝（Al）开展的研究已证实单一材料存在反常的多尺度动力学行为。为实现可靠的对比分析，我们需将上述规律推广至更广泛的材料体系。本研究的成果将揭示描述介尺度缺陷参与熔化过程所需的核心位错物理机制。