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基于直接激光金属烧结成形技术,以FGH95镍基高温合金粉末为研究对象,讨论了烧结工艺参数对制件微观组织、体积密度及显微硬度的影响。制件微观组织结构由等轴晶和枝状晶组成,在较高的激光功率、较低的扫描速度和较小的扫描间距时,等轴晶数量减少,尺寸增加,而枝状晶数量多且晶粒细微。制件的体积密度随着激光功率的提高而增大,随着扫描速率和扫描间距的增大而减小;随着激光功率和扫描速度的提高,制件的显微硬度呈先降后升趋势;随着扫描间距的增大,制件的显微硬度呈递增趋势,在到达最大值时有明显的回落。采用激光功率为900 W,扫描速度为0.8 m/min,扫描间距为0.6 mm以及粉层厚度为0.9 mm的参数组合,可获得表面平整、体积密度高、晶粒均匀细小和无明显微观缺陷的制件,其显微硬度可达到477 HV。
Based on direct laser metal sintering technology, the effect of sintering process parameters on the microstructure, bulk density and microhardness of FGH95 nickel-based superalloy powder was studied. The microstructure of the workpiece consists of equiaxed and dendritic grains. At higher laser powers, lower scanning speeds and smaller scanning pitches, the number of equiaxed grains decreases and the size increases, while the number of dendrites increases Fine grain. The bulk density of the workpiece increases with the increase of the laser power and decreases with the increase of the scan rate and scan spacing. With the increase of laser power and scan speed, the microhardness of the workpiece decreases first and then increases Trend; With the increase of scanning distance, the microhardness of the workpiece shows an increasing trend, when reaching the maximum, there is a clear drop. Using a combination of parameters such as a laser power of 900 W, a scanning speed of 0.8 m / min, a scanning pitch of 0.6 mm, and a ply thickness of 0.9 mm, a smooth surface, high bulk density, uniform fine grains and no microscopic defects are obtained Parts, the micro-hardness up to 477 HV.