AlSi10Mg粉末激光选区熔化残余应力场数值模拟

使用有限元法对AlSi10Mg激光选区熔化残余应力场进行模拟。建立有限元传热模型,将激光热源视为三维高斯体热源,实现在粉床上的移动加载,分别从材料的粉末态与实体态两种单元属性出发,考虑热物性参数和激光能量吸收率随温度变化的特性,进行间接热-应力耦合分析,重点研究激光功率、扫描速度及基板预热温度对残余应力场的影响规律。结果表明:残余应力最大值出现在基板与粉床接触位置,且y向残余应力(平行扫描方向)大于x向残余应力(垂直扫描方向);Von Mises等效应力和y向残余应力随激光功率的增大逐渐增大;随扫描速度的增大逐渐减小;随基板预热温度的升高逐渐降低。

Numerical simulation of selective laser melting residual stress field of AlSi10Mg powder

The finite element method is used to simulate the selective laser melting residual stress field of AlSi10Mg powder.The finite element heat transfer model is established,and the laser heat source is regarded as a three-dimensional Gaussian heat source to realize the moving load on the powder bed.Considering the characteristic of the thermophysical parameters and laser energy absorption rate varying with temperature from the two types of material element properties of powder state and solid state.The indirect thermal-stress coupling analysis is carried out and the influence of laser power,scanning speed and preheating temperature of the substrate on the residual stress field is studied.The results show that the maximum residual stress appears in the contact position between base plate and powder bed,and the y-direction residual stress(parallel scanning direction)is larger than the x-direction residual stress(vertical scanning direction);the Von Mises equivalent stress and the y-direction residual stress gradually increase as the laser power rise,but they gradually decrease as the scanning speed and the preheating temperature of base plate improve.