线、体能量密度对激光选区熔化AlSi10Mg合金致密度及缺陷的影响

Effect of Linear and Volumetric Energy Density on Relative Density and Defects of AlSi10Mg Alloy Prepared by Selective Laser Melting

基于激光选区熔化技术制备AlSi10Mg合金试样,探究线、体能量密度对致密度及孔隙缺陷的影响规律,并通过缺陷微观形貌及熔池特征分析,揭示了缺陷形成机理。结果表明,相同线或体能量密度不同样品的致密度存在明显的差异性,采用线、体能量密度协同分析,不同样品的致密度差值显著降低。当线能量密度为0.12~0.28J·mm^(-1),且体能量密度为30~70J·mm^(-3)时,样品致密度可达99%以上。此外,当线、体能量密度均较低时,形成孔隙形状不规则的未熔合缺陷,位于相邻熔池间且可贯通多个扫描层;当线能量密度较高时,形成孔隙尺寸较大的圆形匙孔缺陷,位于熔池底部。

In this paper,the AlSi10Mg alloy samples were prepared based on the selective laser melting(SLM)technique,and the effect of linear energy density and volumetric energy density on relative density and pore defects were investigated.The formation mechanism of defects were revealed by analyzing of defect microstructure and melt pool characteristics.The results show that the relative density of different samples is obviously different for the same linear/volumetric energy density,and the relative density difference among different samples is significantly reduced by using linear energy density cooperating with volume energy density.The relative density of over 99%is obtained when linear energy density is from 0.12to 0.28J/mm and volume energy density is from 30to 70J/mm^(3).In addition,low linear and volumetric energy densities result in irregular lackof-fusion defects that traverse multiple melt pool layers,while high linear energy density leads to the formation of circular keyhole defects with large pore sizes located at the base of the melt pool.