位错与溶质原子间动态相互作用的数值模拟研究

通过Cottrell-Bilby型溶质动力学模型，对位错线周围的溶质原子浓度随应变率的变化进行了研究，并得到了三种不同的位错-溶质相互作用方式：在低应变率时，位错被溶质原子气团充分钉扎，它上面的溶质浓度近似达到饱和；在高应变率时，脱钉作用占主导地位，位错运动几乎不受深质影响；而在中间应变率时，位错反复经历着钉扎和脱钉过程，动态应变时效发生.此外，通过对模型方程的推导，还自然地得到了平衡状态下率相关流动应力与应变率之间的N形关系曲线. 关键词： 位错 溶质原子 动态应变时效 数值模拟

Numerical simulation of the dynamic interactions between dislocation and solute atoms

Using the Cottrell-Bilby kinetics model for solute atoms, evolution of the solute concentration around dislocation line has been investigated with respect to the strain rate. Three types of interactions between dislocation and solutes were obtained: At low strain rates, the dislocation is effectively pinned by its condensed solute cloud and the solute concentration remains almost at its saturation value. At high strain rates, the npinning effect predominates and dislocation moves at high velocity with little solute disturbance. While at the intermediate strain rates, the aging and unpinning effects take place alternately and dynamic strain ageing operates. Morevover, the N-shaped relationship between the rate-dependent flow stress and strain rate has also been naturally deduced from the model equations without additional assumptions.