选择性激光熔化制备纯钨块体材料的研究

采用选择性激光熔化技术制备了纯钨块状样品, 研究了激光参数对所制备样品的表面形貌、内部晶粒组织和密度的影响。结果表明, 随着激光能量密度的增加, 样品表面变得光滑, 样品内部孔隙减少, 密度提高。采用功率300 W、扫描速率200 mm?s-1的激光扫描参数制备出了相对密度为97%的纯钨块状样品; 当激光功率提高至350 W时, 由于裂纹增多使样品密度下降; 随着激光输入能量密度的增加, 选择性激光熔化制备的样品内部晶粒方向性变得明显, 且晶粒尺寸增大; 采用扫描策略2 (激光功率200 W, 激光扫描速度200 mm?s-1)进行制备的样品内部孔隙较多, 且孔隙大多沿样品增材制造高度方向呈一条直线分布, 样品内部部分晶粒沿样品增材制造高度方向伸长。

Study on the tungsten bulk materials prepared by selective laser melting

The tungsten bulk materials were prepared by selective laser melting (SLM) in this paper. The effects of SLM processing parameters on surface morphology, microstructures, and density of tungsten parts were investigated. The results indicate that, the number of internal pores in SLM samples is reduced with the increase of input laser energy density. The density is increased with the improvement of laser power and the decrease of laser scanning speed. The pure tungsten block sample with a relative density of 97% is prepared in the laser power of 300 W at the scanning speed of 200 mm?s-1. However, when the laser power raises to 350 W, the density of bulk tungsten sample decreases due to the enhancement of cracks. The grain is enlarged and elongated along the height direction in additive manufacturing with the increase of input laser energy density. The inside pores are increased and distributed along the height direction in additive manufacturing by using laser scanning strategy 2 (laser power 200 W and scanning speed of 200 mm?s-1). Moreover, some of grains inside sample prepared by laser scanning strategy 2 are elongated along the height direction in additive manufacturing.