反冲压力作用下激光选区熔化熔池热动力学行为  

The Role of Recoil Pressure in Thermodynamic Behaviors of Molten Pool during Selective Laser Melting

作　　者：袁伟豪 陈辉[1,2] 魏青松 YUAN Weihao;CHEN Hui;WEI Qingsong(State Key Lab of Materials and Die&Mould Technology,School of Materials Science and Engineering,Huazhong University of Science and Technology,Wuhan 430074;Department of Mechanical Engineering,National University of Singapore,Singapore 117575)

机构地区：[1]华中科技大学材料成形与模具技术国家重点实验室,武汉430074 [2]新加坡国立大学机械工程学院,新加坡117575

出　　处：《机械工程学报》2020年第7期213-219,共7页Journal of Mechanical Engineering

基　　金：国家自然科学基金(51775207,51705170);华中科技大学学术前沿团队、武汉市科技计划(2018010401011281);中国博后科学基金(2018T 110756)资助项目。

摘　　要：激光选区熔化(SLM)过程中,金属蒸发产生的反冲压力会改变熔池的热力学行为,导致零件缺陷。以316L不锈钢粉末为对象,通过数值模拟和试验测试,分析了不同激光工艺参数下反冲压力对熔池温度场和速度场的影响规律。其中,数值模型基于VOF多相流原理,充分考虑金属蒸发的反冲压力,同时结合了界面追踪热源模型。结果表明:固定激光线能量密度为300J/m时,较大的扫描速度(1.0m/s)会得到沿扫描方向更大范围的熔池,也会产生更深的凹陷;当激光扫描速度一定时(1.0m/s),熔池凹陷深度随激光功率增大而增大;并且凹陷深度越大,熔池深度越大,但沿扫描方向的熔池范围、熔化道表面形貌和宽度变化不大。During selective laser melting(SLM) process, the recoil pressure induced by metal evaporation affects the thermodynamic behaviors of molten pool, which may result in forming defects. Taking 316 L stainless steel as an example, through computational and experimental methods, the effects of the recoil pressure on the thermodynamic behaviors of the molten pool are fully investigated. The established model is based on volume of fluid(VOF) multiphase theory with full consideration of recoil pressure combining ray-tracing heat source model. From the results, with a fixed laser linear energy density, the lager the laser scanning speed, the wider the molten pool range and larger the depression depth. With a fixed laser scanning speed(1.0 m/s), the larger the laser power, the larger depression depth, which further lead to elevated depth of molten pool, but the molten pool length along scanning direction, the width and surface morphology of solidified tracks change little.

关 键 词：激光选区熔化 反冲压力 熔池 凹陷 表面形貌 

分 类 号：TG156[金属学及工艺—热处理]