体能量密度对选区激光熔化成形Hastelloy X合金组织及性能的影响

Effect of Volumetric Energy Density on Microstructure and Properties of Hastelloy X Alloy Manufactured by Selective Laser Melting

采用选区激光熔化(SLM)技术制备了Hastelloy X合金,研究了体能量密度(18.3,29.8,30.3,44.9,46.3,50.9,58.8,61.7,88.4J·mm^-3)对合金微观形貌、显微组织、密度和硬度的影响。结果表明:SLM成形Hastelloy X合金纵截面形貌呈鱼鳞状,在熔池区域存在等轴晶、树枝晶及跨越多个沉积层的柱状晶,晶粒宽度为0.61.2μm;体能量密度在18.346.3J·mm^-3时,合金内部存在孔隙缺陷,随着体能量密度的继续增加,孔隙逐渐减少并消失,同时微裂纹开始形成并逐渐增多;合金的密度和硬度随体能量密度增加先增加后趋于稳定;当体能量密度为50.9J·mm^-3时,合金中的孔隙和微裂纹最少,成形效果最好。

Hastelloy X alloy was manufactured by selective laser melting(SLM)technique,and the effect of volumetric energy density(18.3,29.8,30.3,44.9,46.3,50.9,58.8,61.7,88.4 J·mm^-3)on micromorphology,microstructure,density and hardness of the alloy was investigated.The results show that the longitudinal section morphology of the Hastelloy X alloy manufactured by SLM was fish-scale-line morphology.Equiaxed crystals,dendrite and columnar grains spanning multiple deposited layers were present in the molten pool area,and the width of grains was about 0.6-1.2μm.When the volumetric energy density was 18.3-46.3 J·mm^-3,there were pore defects in the alloy.As the volumetric energy density continued to increase,the pore gradually decreased and disappeared,and microcracks emerged and gradually increased.The density and hardness of the alloy increased first and then tended to be stable with the volumebric energy density increasing.The alloy with volumetric energy density of 50.9 J·mm^-3 had the least porosity and cracks,and the formability was the best.