二元系纳米多层薄膜非线性互扩散研究

采用非均匀体系非线性动力学离散模型计算AB二元系纳米多层薄膜的非线性互扩散,研究了A、B原子间作用力之差VBB-VAA和有序能V对纳米多层薄膜浓度分布和界面结构的影响.对于V≤0的纳米多层薄膜,随着VSS-VAA由0减小到-0.05eV,扩散过程中多层薄膜浓度偏离对称分布,界面由宽化向平直转变,有序能V由0减小到-0.025eV,导致多层薄膜的扩散速度加快.当V>0时,扩散过程中多层薄膜出现相分离趋势导致的上坡扩散,初始宽化互混的界面变得平直,且随着VBB-VAA由0减小到-0.05V,多层薄膜扩散过程中形成的浓度起伏长大成为新的亚层.AB二元系纳米多层薄膜扩散过程中的浓度分布和界面结构演变与扩散非对称性系数m'、有序能V和初始时刻的浓度梯度有关.

Nonlinear Interdiffusion in Binary Nanometer-scale Multilayers

The nonlinear interdiffusion in binary AB nanometer-scale multilayers is calculated by the nonlinear kinetic discrete model for nonuniform system, to study the effect of VBB-VAA and ordering energy V on the concentration profile and interface structure in the multilayers. For the mnltilayers of V≤0, with VBB-VAA decreasing from 0 to-00. 05eV, the concentration profile of the multilayers deviates from symmetrical distribution and their interfaces become sharp. The calculated diffusion time decreases with the ordering energy V changing from 0 to-0. 025eV. For V>0, the uphill diffusion takes place due to the phase separation tendency and the initial broad interface become sharp in the multilayers during interdiffusion. The concentration wave formed during interdiffusion turns into a new sublayer as VBB-VAA decreases from 0 to-0. 05eV. It is found that the nonlinear interdiffusion of binary nanometer-scale multilayers is related to the diffusion asymmetry coefficient m', the ordering energy V and the initial concentration gradient of multilayers.