选区激光熔化成形Mg-Y-Sm-Zn-Zr合金的流场数值模拟

Numerical Simulation of Flow Field of Mg-Y-Sm-Zn-Zr Alloy Formed by Selective Laser Melting

摘要:

基于离散元法和有限体积法建立了选区激光熔化（SLM）成形Mg-3.4Y-3.6Sn-2.6Zn-0.8Zr合金粉末尺度的三维模型，模拟了激光功率、扫描速度及激光线能量密度对流体流动的影响，分析了熔池内金属熔化、流体流动及凝固成形过程等问题。结果表明，增加激光功率与降低扫描速度对熔池内溶质流动的影响本质上是一致的。当扫描速度一定时，激光功率为100 W时，流体流速最大为4.914 m/s。熔池温度较高时熔融液体蒸发带来的反冲压力导致熔池凹陷。

Abstract:

A powder-scale three-dimensional model of the selective laser melting (SLM) process for Mg-3.4Y-3.6Sm-2.6Zn-0.8Zr alloy was established by the discrete element method and the finite volume method, and the effects of laser power, scanning speed and laser line energy density on the fluid flow in the molten pool were simulated. The problems of metal melting, fluid flow and solidification and forming process in the molten pool were analyzed. Results show that the effects of increasing the laser power or decreasing the scanning speed on the solute flow in the molten pool are essentially the same. At a certain scanning speed, the maximum fluid flow rate is 4.914 m/s when the laser power is 100 W. The recoil pressure due to the evaporation of the molten liquid at higher molten pool temperatures leads to the depression of the molten pool.