Wang Xiang, Kang Jinwu, Wang Tianjiao, Wu Pengyue, Feng Tao, Zheng Lele
School of Materials Science and Engineering, Key Laboratory for Advanced Materials Processing Technology, Tsinghua University, Beijing 100084, China.
Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen 518055, China.
Materials (Basel). 2019 Jul 5;12(13):2165. doi: 10.3390/ma12132165.
Selective laser melting (SLM) is a promising powder bed fusion additive manufacturing technique for metal part fabrication. In this paper, varying scanning speed in the range of 500 mm/s to 1900 mm/s, and laser power in the range of 100 W to 200 W, were realized from layer to layer in a cycle of 56 layers in a single cuboid Inconel 718 alloy specimen through SLM. Layer-wise variation of microstructure and porosity were acquired, showing the layer-wise controlling capability of microstructural soundness. The melt pool size and soundness are closely linked with the energy input. High energy density led to sound regions with larger, orderly stacked melt pools and columnar grains, while low energy density resulted in porous regions with smaller, mismatched melt pools, un-melted powder, and equiaxed grains with finer dendrites. With the increase of laser energy density, the specimen shifts from porous region to sound region within several layers.
选择性激光熔化（SLM）是一种用于制造金属零件的很有前景的粉末床熔融增材制造技术。在本文中，通过SLM在一个长方体镍基合金718试样的56层循环中逐层实现了500毫米/秒至1900毫米/秒范围内的扫描速度变化以及100瓦至200瓦范围内的激光功率变化。获得了微观结构和孔隙率的逐层变化情况，显示出微观结构健全性的逐层控制能力。熔池尺寸和健全性与能量输入密切相关。高能量密度导致具有较大、有序堆叠熔池和柱状晶粒的健全区域，而低能量密度则导致具有较小、不匹配熔池、未熔化粉末以及具有更细枝晶的等轴晶粒的多孔区域。随着激光能量密度的增加，试样在几层内从多孔区域转变为健全区域。
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