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针对K640钴基合金粉末进行选区激光熔化(SLM)成形工艺优化实验,以期获得高致密度K640合金的工艺参数。在固定层厚条件下,研究了激光功率、扫描速度、扫描间距、扫描线长度对致密度的影响,分析优化参数下成形件的显微组织,探讨激光线能量密度与成形件粗糙度以及维氏硬度的关系。研究结果表明,成形件致密度随着激光线能量密度的增加呈先增大后减小趋势,随着扫描间距和扫描线长度的增加,致密度不断减小,最终在激光功率190 W、扫描速度800mm/s、扫描间距0.08mm、扫描线长度0.08mm下获得98.2%高致密度试样;成形件上表面和侧面粗糙度结果相差较大,上表面粗糙度随着激光线能量密度的增加而缓慢减小,而激光线能量密度对侧面粗糙度并无明显影响;选区激光熔化成形的K640合金平均硬度达到500HV,高于传统铸造K640合金硬度。
Aiming at the process optimization of the K640 Co-based alloy powder, the process of the selective laser melting (SLM) forming process was studied in order to obtain the process parameters of high density K640 alloy. The effects of laser power, scanning speed, scanning pitch and scanning line length on the density were studied under fixed layer thickness conditions. The microstructure of the shaped part under the optimized parameters was analyzed. The relationship between the laser energy density and the roughness of the formed part and the dimension Hardness of the relationship. The results show that the densification density increases first and then decreases with the increase of laser energy density, and the density decreases with the increase of scan pitch and scan line length. Finally, at a laser power of 190 W, Speed of 800mm / s, scanning pitch of 0.08mm, scanning line length of 0.08mm to obtain a high density sample of 98.2%; the shape of the upper surface and the side of the roughness difference between the larger, the upper surface roughness as the laser line energy density increases While the laser line energy density has no obvious effect on the side roughness. The average hardness of the laser melting K640 alloy in the selected area reaches 500 HV, which is higher than the hardness of the traditional cast K640 alloy.