基于蒙特卡洛方法的搅拌摩擦焊晶粒生长模拟  

Monte Carlo based simulation of grain growth in friction stir welding

作　　者：张昭[1] 吴奇[1] 万震宇[1] 张洪武[1] 

机构地区：[1]大连理工大学工程力学系工业装备结构分析国家重点实验室,大连116024

出　　处：《塑性工程学报》2015年第4期172-177,共6页Journal of Plasticity Engineering

基　　金：国家自然科学基金资助项目(11172057);国家重点基础研究发展(973)计划资助项目(2011CB013401);中央高校基本科研业务费专项资金;新世纪优秀人才支持计划

摘　　要：搅拌摩擦焊接焊后材料微观晶粒结构对构件焊后的力学性能有重要影响。在搅拌摩擦焊接数值模拟的基础上,采用蒙特卡洛模拟方法研究了焊后构件截面晶粒尺寸的分布规律。结果表明,在搅拌区域,母材受搅拌针作用后破碎细化的致密晶粒为初始生长形貌;在热力影响区,材料受到轴肩旋转拉伸的作用,跟踪材料的物质点可得到拉伸比例,并作用于母材晶粒,得到该区域初始晶粒的形貌;热影响区的晶粒变化表现为母材晶粒在温度场作用下的生长。蒙特卡洛迭代步数由材料边界扩展速度推导确定,其受材料经历的温度历程影响。研究结果与文献中晶粒尺寸的分布规律相符,验证了模型用于预测搅拌摩擦焊接晶粒生长的可行性。The microstructure in friction stir weld is important in the determination of the mechanical properties of the welded joint, In this work, the Monte Carlo method was implemented in a coupled thermal mechanical model to predict the grain size dis- tribution after friction stir welding. In stirring zone, the base grains are broken and recrystallized into small and fine grains. In the heat and mechanical affected zone, the grains suffered extension from the tool rotations, and the extension ratios computed from the traced material particles are then used in the grain growth process. The grains in the heat affected zone are only influ enced by the temperature field. The steps of Monte Carlo simulation are calculated from the grain boundary migration model, which is mainly influenced by the temperature cycle. The predicted results are compared with the experimental values from literatures for validation of the current method.

关 键 词：搅拌摩擦焊 热力耦合模型 蒙特卡洛方法 晶粒生长 

分 类 号：TG456.9[金属学及工艺—焊接]