应力场对相分解过程影响的计算机模拟研究（Ⅱ）——非对称成分及拐点以下的相分离模拟

Effect of Stress Field on Phase Separation Process by Computer Simulation (II): Simulation of Asymmetrical and below Spinodal Composition Phase Separation Process

摘要:

采用扩散界面场模型对非对称成分点及拐点以下成分点同构两相分解过程中应力场（包括外场）对析出相的形态及动力学过程的影响作了比较系统的研究.模拟结果表明：对于各向异性系统在相分解过程中由于弹性应变能与界面能间的相互作用将会导致析出相在不同阶段呈现不同的形貌如网格结构、三明治多畴结构、沉淀宏观点阵结构以及板条状等;对于非均匀弹性模量系统在外加应力场作用下,沉淀相的析出过程发生重大的变化,粒子沿弹性软方向呈各向异性析出.此外,模拟结果还发现,在应力场（包括外加场情况）存在条件下,相析出的中前期长大过程中小粒子沿着弹性软方向相互联结成大粒子,在相变后期孤立的小粒子被大粒子的长大所消耗.

Abstract:

Morphological evolutions and kinetics process controlled by transformation-induced elastic strain (include external strain field) during isostructure phase separation are systematically investigated using prototype binary alloy by diffuse-interface field model. The results show that various types of morphologies, such as basket-weave structures, sandwich-like multi-domain structures, precipitate macro lattices and plate-like structures, are predicted in different stages of phase separation. It is demonstrated that the precipitates are preferentially oriented with an external stress for an inhomogeneous elastic modulus system. Moreover, the simulation results also indicate that the small particles will be connected along elastic soft directions to formation bigger particles in the stage of growth and those small isolated particles will be consumed by bigger particles in the stage of ripening.