Athermal Resistance to Phase Interface Motion Due to Precipitates: A Phase Field Study
Athermal Resistance to Phase Interface Motion Due to Precipitates: A Phase Field Study
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DOI：
10.2139/ssrn.4156059
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发表时间：
2022-06
期刊：
影响因子：
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通讯作者：
M. Javanbakht;V. Levitas
中科院分区：
文献类型：
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作者：
M. Javanbakht;V. Levitas
研究了沉淀物引起的相界面运动的非热阻。在相变过程中，求解了耦合相场方程和弹性方程。使用误差函数和矩形函数计算了沉淀物引起的体积失配应变。由于析出物的存在，正向PTS和反向PTS的临界热驱动力明显不同，导致了滞后行为。对于较小的析出半径与界面宽度相比，失配应变对临界热驱动力几乎没有影响。此外，对于正向和反向PTS，临界热驱动力值都随着沉淀浓度的增加而非线性增加。析出物表面能的变化显著改变了PT的形貌和临界热驱动力。与界面宽度相比，对于较大的析出物尺寸，临界热驱动力依赖于失配应变。对于沉淀表面的恒定表面能(CSE)和变表面能(VSE)边界条件，直接PT的临界热驱动力与失配应变系数成线性关系，而反向PT的临界热驱动力与失配应变系数几乎无关。对于较大的析出物，直接PT的临界热驱动力与析出物浓度呈非线性关系。然而，对于反向PT，其CSE BCS的值与析出物浓度呈线性增加，而与VSE BCS的析出物浓度几乎无关。此外，对于任何浓度，VSE BCS都会导致较高的热临界驱动力、较小的滞后范围和较大的变化率。利用热力学相平衡条件对得到的临界微观组织和热驱动力进行了验证。所得结果有助于在纳米尺度上更好地理解界面的非热摩擦机制以及类似的缺陷效应。
Athermal resistance to the motion of a phase interface due to a precipitate is investigated. The coupled phase field and elasticity equations are solved for the phase transformation (PT). The volumetric misfit strain due to the precipitate is included using the error and rectangular functions. Due to the presence of precipitates, the critical thermal driving forces remarkably differ between the direct and reverse PTs, resulting in a hysteresis behavior. For the precipitate radius small compared to the interface width, the misfit strain does not practically show any effect on the critical thermal driving force. Also, the critical thermal driving force value nonlinearly increases vs. the precipitate concentration for both the direct and reverse PTs. Change in the precipitate surface energy significantly changes the PT morphology and the critical thermal driving forces. The critical thermal driving force shows dependence on the misfit strain for large precipitate sizes compared to the interface width. For both the constant surface energy (CSE) and variable surface energy (VSE) boundary conditions (BCs) at the precipitate surface, the critical thermal driving force linearly increases vs. the misfit strain coefficient for the direct PT while it is almost independent of it for the reverse PT. For larger precipitates, the critical thermal driving force nonlinearly increases vs. the precipitate concentration for the direct PT. For the reverse PT, however, its value for the CSE BCs linearly increases vs. the precipitate concentration while it is almost independent of the precipitate concentration for the VSE BCs. Also, for any concentration, the VSE BCs result in higher thermal critical driving forces, a smaller hysteresis range, and a larger transformation rate. The obtained critical microstructure and thermal driving forces are validated using the thermodynamic phase equilibrium condition for stationary interfaces. The obtained results help for a better understanding of athermal friction mechanism for interfaces and similar defect effects on various PTs at the nanoscale.