固体中的扩散应力研究

DIFFUSION-INDUCED STRESSES IN SOLIDS

固体中原子的互扩散行为导致的扩散应力不仅可以引起材料的宏观变形,而且可能在材料内部形成特殊的微观组织．系统阐述了固体中原子扩散与应力之间的相互作用问题,区别了应力扩散与扩散应力的概念,并通过流点体积生长率的推导,建立了互扩散区域内流点应力、应变与原子扩散流之间的变量关系,提出描述固态互扩散区域内扩散应力与应变的一般理论．在此基础上,分析了固态反应周期层片型结构的形成机理和薄片扩散偶的扩散弯曲问题,并提供了相应的理论解释．

Recent experiments indicate that stresses induced by atomic interdiffusion in solids can not only result in the macro-distortion of materials, but also form some peculiar micro-structures in the materials. Considered that little has been known in a detailed way of the mechanisms of diffusioninduced stresses, the relationship of atomic diffusion and stresses in solids will be elucidated and the concepts of creep-induced diffusion and diffusion-induced stresses are clarified in this paper. Based on the volume growth rate of a flow point, an equation is obtained for the relationship of stresses of flow point and atomic diffusion fluxes and therefore a general theory is constructed to describe the phenomena of diffusion-induced stresses and strains, e.g., the bending of thin diffusion couples and the periodic layer formation during solid state reactions.