摘要
针对岛式扫描策略进行三维有限元仿真,并采用蛇形扫描方式进行对比。综合考虑热传导、热辐射和热对流效应,合金材料热物理性能参数与温度的非线性关系及相变潜热的影响,建立了三维瞬态金属选区激光熔化(SLM)有限元模型。分析结果表明,SLM成形过程中,熔池呈水滴状,前端温度等值线比后端细密。与蛇形扫描方式相比,岛式扫描方式下岛屿边缘会出现温度二次升高现象,试件整体温度场分布均匀,有利于减小应力集中。温度场特点直接影响β相柱状晶的大小,岛式扫描方式更易形成较粗的β相柱状晶。分区扫描对岛屿边界影响较为明显,与岛屿内部相比,相邻的岛屿间搭接质量较差。
Three-dimensional finite element simulation is used to investigate the temperature field with the island scanning strategy paralleled with the S-shaped scanning strategy. Considering the influence of heat conduction,heat radiation and heat convection, nonlinear relationship between thermophysical properties of metal material and temperature, and enthalpy processing utilizing latent heat of phase change, a finite element model of metal selective laser melting（SLM） is established. It is found that the molten pool is in the shape of a water droplet, and the temperature contour at front-end is denser than that at back-end. Compared with the S-shaped scanning strategy, island scanning has the phenomenon of secondary temperature elevation at the island edge. The whole temperature field of the model is uniform, which is beneficial to reducing the stress concentration. It was observed that the average width of the β phase in the samples built with the island scanning strategy is significantly larger than that with the S-shaped scanning strategy. The influence of the island scanning on the boundary of the islands is quality of overlapping areas, and the overlap between adjacent islands is poor.
出处
《中国激光》
EI
CAS
CSCD
北大核心
2016年第4期68-74,共7页
Chinese Journal of Lasers
基金
国家自然科学基金(51375242)
江苏省优势学科资助项目
关键词
激光技术
选区激光熔化
温度场
有限元模拟
扫描策略
显微组织
laser technique
selective laser melting
temperature field
finite element simulation
scanning strategy
microstructure
