发表机构
Joint Institute for High Temperatures; Joint Institute for Nuclear Research（高温联合研究所; 核物理联合研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究利用神经网络分子动力学模拟，揭示了B2-NiAl在高压下熔化温度随压力显著升高，且熔化过程保持同成分熔化，为理解其高压热力学行为提供了原子级证据。
AI 中文摘要
我们利用深度势能（Deep Potential）原子间相互作用模型的神经网络分子动力学方法，研究了有序B2-NiAl合金的压力依赖熔化行为。通过在宽广的压力范围内进行固液两相共存模拟，确定了熔化温度，得到了熔化曲线$T_m(P)$。与现有的实验和先前分子动力学结果相比，本计算预测在高压压缩下熔化温度随压力的增加更为显著。为评估计算熔化线的热力学一致性，我们计算了熔化时的焓变和体积变化，并将Clapeyron斜率与拟合的$T_m(P)$曲线的导数进行了比较。在大部分研究的压力范围内，两种估计吻合良好，支持了共存结果的内在一致性。为探究熔化特性，我们对共存构型进行了逐层成分分析，发现在所有研究的压力下，共存的液体基本保持等原子比，铝组分偏离化学计量比不超过$5\ imes10^{-3}$。这提供了直接的原子级证据，表明在当前模型下B2-NiAl的熔化保持同成分熔化。综合这些结果，我们建立了热力学一致的压力依赖的B2-NiAl熔化描述，并阐明了其在压缩下的熔化特性。
英文摘要
We investigate pressure-dependent melting of ordered B2-NiAl using neural-network molecular dynamics with a Deep Potential interatomic model. Melting temperatures are determined from two-phase solid-liquid coexistence simulations over a broad pressure range, yielding the melting curve $T_m(P)$. Relative to available experimental and previous molecular-dynamics results, the present calculations predict a stronger increase of the melting temperature with pressure at elevated compression. To assess the thermodynamic consistency of the calculated melting line, we evaluate the enthalpy and volume changes upon melting and compare the Clapeyron slope with the derivative of the fitted $T_m(P)$ curve. The two estimates are in good agreement over most of the investigated pressure range, supporting the internal consistency of the coexistence results. To probe the character of melting, we perform a layer-resolved composition analysis of the coexistence configurations and find that the coexisting liquid remains essentially equiatomic at all studied pressures, with deviations of the aluminum fraction from the stoichiometric value not exceeding $5\times10^{-3}$. This provides direct atomistic evidence that melting of B2-NiAl remains congruent within the present model. Together, these results establish a thermodynamically consistent pressure-dependent melting description of B2-NiAl and clarify the character of its melting under compression.
