论文部分内容阅读
晶粒静态粗化是一种重要的物理现象,严重影响微观结构的演化和材料的力学性能.如何有效模拟这一过程已经成为该领域的研究热点.本文通过考虑溶质原子拖拽效应和晶界迁移各向异性对晶粒粗化的影响,建立了元胞自动机模型,并对钛合金单相区静态粗化过程进行了模拟.为了描述不同溶质原子的拖拽效应对粗化的影响,文中将溶质原子在beta相中的扩散速度等效转化成钛原子的迁移速度.为此,提出了定量描述溶质原子扩散速度与钛原子迁移速度之间转化关系的数学表达式.其中,表达式中考虑了影响溶质原子扩散速度的因素如溶质原子的半径、原子质量及晶格类型.通过引入参数c0考虑晶界迁移各向异性对粗化的影响.当c0为1时,则认为晶界迁移为各向异性,若为0时则认为是各向同性.将上述表达式应用到元胞自动机模型中,模拟钛合金(包括TC4,Ti17,TG6和TA15)在单相区的静态粗化现象.预测结果包括粗化动力学和组织演化与试验进行了对比,而且较为吻合.最后,讨论了时间、温度和化学成分对粗化的影响,以及本文元胞自动机模型预测粗化的局限性.
Static coarsening of grains is an important physical phenomenon that seriously affects the evolution of microstructure and the mechanical properties of materials.How to simulate this process effectively has become a hot research topic in this field.Through the consideration of the drag effect of solute atoms and the grain boundary Migration anisotropy on the coarsening of grains, a cellular automata model was established and the static coarsening process was simulated in the single phase region of titanium alloy.In order to describe the effect of drag effect of different solute atoms on coarsening, In this paper, the diffusion speed of solute atoms in the beta phase is equivalently converted into the migration speed of titanium atoms.Therefore, a mathematical expression quantitatively describing the transformation relationship between the diffusion speed of solute atoms and the migration speed of titanium atoms is proposed, in which the expression Consider the factors that affect the diffusion speed of solute atoms, such as the radius of solute atoms, atomic mass and lattice type. Considering the influence of grain boundary anisotropy on the coarsening by introducing the parameter c0, when c0 is 1, the grain boundary Migration to anisotropy, if it is 0 is considered isotropic. The above expressions are applied to cellular automata model, simulation of titanium alloys (including TC4, Ti17, TG6 and TA15) in a single The results of the prediction include the coarsening kinetics and the evolution of the microstructure and the experiment are contrasted with each other and are in good agreement.Finally, the effects of time, temperature and chemical composition on coarsening are discussed, and the cellular automaton model Predict the limitations of coarsening.