摘要
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。
Microstructure and mechanical performances of samples prepared by direct laser metal sintering （DLMS） technique with FGH95 superalloy were discussed. The experiment parameters that effected on the microstructure, the density and the micro-hardness of sample were analyzed systematically. Two kinds of crystal morphology appeared in the microstructure, one was equiaxial structure and the other was the dendrite structure. Size and number of these two kinds of crystal morphology varied with different parameters. The equiaxial structure has been trended to the dendrite structure and the density and micro-hardness of sample have been increased with the larger laser power, the slower scanning speed or the smaller scanning spacing in a certain range. In this certain range of parameters, a set of parameters, such as laser power of 900 W, scanning speed of 0.8 m/min, scanning spacing of 0.6 mm and thickness of 0.9 mm, have been achieved to fabricate an ideal sample that is provided with smooth sintering surface, fine crystal, higher micro-hardness and less micro-defect. The micro-hardness of the sample can reach 477 HV.
出处
《中国激光》
EI
CAS
CSCD
北大核心
2011年第1期70-75,共6页
Chinese Journal of Lasers
基金
南京航空航天大学基本科研业务费专项(NS2010144)
湖南省教育厅科研基金项目(10c341)资助课题
关键词
激光技术
直接激光金属烧结
微观组织
显微硬度
工艺参数
laser technique
direct laser metal sintering
microstructure
micro-hardness
technology parameters
