AI 中文总结
研究采用MC采样与MD方法结合MACE-OMAT-0势，揭示四种高熵过渡金属碳化物的晶界偏聚规律，发现不同VI族元素对应不同晶界预熔化温度，明确界面化学对预熔化的关键作用。
AI 中文摘要
采用蒙特卡洛（MC）采样与结合通用机器学习原子间势MACE-OMAT-0的分子动力学（MD）方法，对四种高熵过渡金属碳化物的晶界偏聚及热诱导界面无序化展开研究。MC采样显示，VI族元素（Cr、Mo或W）与Zr偏聚至晶界，晶界处VI族元素含量约达45 at.%，与STEM-EDS观测结果一致。MD加热过程中，晶界林德曼指数（衡量原子间距波动的归一化指标）在Cr基碳化物中于约1390℃达到类液态阈值δ=0.15，Mo基对应为1660℃，W基为1890℃，而晶粒内部始终低于该阈值。化学随机的（Cr,Hf,Ta,Ti,Zr）C参考体系约晚60℃达到阈值，且界面局部无序程度更低，凸显界面化学在预熔化中的作用。分物种位移分析显示晶界迁移率提升，尤其碳的迁移率更高。总体而言，富Cr界面呈现最早且最显著的类预熔化响应，其次是含Mo、W的界面。
英文摘要
Grain-boundary segregation and thermally induced interfacial disordering were investigated in four high-entropy transition metal carbides using Monte Carlo (MC) sampling and molecular dynamics (MD) with the universal MACE-OMAT-0 machine-learning interatomic potential. MC sampling segregated the group-VI element (Cr, Mo, or W) and Zr to grain boundaries, where the group-VI content reached approximately 45 at.%, consistent with STEM-EDS observations. During MD heating, the grain-boundary Lindemann index, a normalized measure of interatomic distance fluctuations, reached the liquid-like threshold of $δ=0.15$ near $1390^{\circ}\mathrm{C}$ for the Cr-containing carbides, $1660^{\circ}\mathrm{C}$ for Mo, and $1890^{\circ}\mathrm{C}$ for W, while the grain interiors remained below the threshold. A chemically random (Cr,Hf,Ta,Ti,Zr)C reference crossed about $60^{\circ}\mathrm{C}$ later and showed less boundary-localized disorder, highlighting the role of interfacial chemistry in premelting. Species-resolved displacements showed enhanced grain-boundary mobility, particularly for carbon. Overall, Cr-rich interfaces showed the earliest and most extensive premelting-like response, followed by Mo- and W-containing boundaries.
Comments12 pages, 6 figures
