Wang Yashen, Liang Zun, Zhang Xin, Lu Wenliang, Yu Zhiyong, Ma Xiangming, Liang Hongtao, Yang Yang
State Key Laboratory of Precision Spectroscopy, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, People's Republic of China.
State Key Laboratory of Advanced Special Steel, Shanghai Key Laboratory of Advanced Ferrometallurgy, Shanghai University, Shanghai 200444, People's Republic of China.
J Phys Condens Matter. 2022 Apr 27;34(26). doi: 10.1088/1361-648X/ac6647.
By employing the non-equilibrium molecular dynamics (MD) simulations and the time-dependent Ginzburg-Landau (TDGL) theory for the solidification kinetics, we predict the kinetic coefficients for the bcc(100), (110), and (111) CMIs of the soft-spheres, which are modeled with the inverse-power repulsive potential, and compare with the previous reported data of the bcc Fe system. We confirm a universal-like behavior of the spatial integrations of the (density wave amplitudes) Ginzburg-Landau order parameter square-gradient for the bcc CMI systems. The TDGL predictions of the kinetic anisotropies for bcc soft-sphere and bcc Fe CMI systems are identical; both agree well with the MD measurement for the soft-sphere system but differ strongly with the MD measurement for the Fe system. This finding implies that the current TDGL theory reflects a preference of presenting the generic anisotropy relationship due to the interfacial particle packings but lacks the contribution parameter which addresses the specificities in the kinetic anisotropies owing to the particle-particle interactions. A hypothesis that the density relaxation times for the interface melt phases to be anisotropic and material-dependent is then proposed.
通过采用非平衡分子动力学（MD）模拟以及用于凝固动力学的含时金兹堡 - 朗道（TDGL）理论，我们预测了由逆幂排斥势建模的软球体系中体心立方（bcc）（100）、（110）和（111）晶体学微观结构单元（CMIs）的动力学系数，并与先前报道的体心立方铁体系的数据进行比较。我们证实了体心立方CMI体系的金兹堡 - 朗道序参量平方梯度的（密度波振幅）空间积分具有类普遍行为。体心立方软球和体心立方铁CMI体系的动力学各向异性的TDGL预测结果相同；两者与软球体系的MD测量结果吻合良好，但与铁体系的MD测量结果差异很大。这一发现表明，当前的TDGL理论反映了由于界面粒子堆积而呈现出的一般各向异性关系的偏好，但缺乏解决由于粒子 - 粒子相互作用导致的动力学各向异性特异性的贡献参数。随后提出了一个假设，即界面熔体相的密度弛豫时间是各向异性且依赖于材料的。
