选区激光熔化钴铬合金的组织及性能研究

Study on Microstructure and Properties of Selective Laser Melting Co-Cr Alloy

利用光纤半导体激光器在钴铬合金粉末床上进行选区激光熔化单道扫描试验。借助光学显微镜和X射线衍射仪对该合金的形貌、相组成进行了分析,使用显微硬度计测试了钴铬合金的显微硬度。结果表明:选区激光熔化钴铬合金的相主要由γ-Co、Cr_(23)C_6和Cr_7C_3组成;显微组织主要由定向生长的柱状树枝晶和粗大树枝晶组成,熔池中心部位的树枝晶粗大,并且有"颈缩"现象;显微硬度从熔池边界到中心逐渐降低,但靠近中心区域的显微硬度有一定的波动。

The selective laser melting single channel scanning experiment was perfromed on Co-Cr alloy powder bed by using fiber diode laser. The morphology and phase composition of the alloy were characterized by optical microscope and X-ray diffractometer, and the microhardness of Co-Cr alloy was tested by microhardness tester. The results show that the phases of selective laser melting Co-Cr alloy are mainly composed of γ-Co, Cr23C6 and Cr7C3. The microstructure mainly consists of directional columnar crystals and thick dendrites. The dendrites in the center of the molten pool are thick with the phenomenon of ＂necking＂ existing. The microhardness gadually decreases from the boundary of the molten pool to the center, but the microhardness near the center fluctuates in a certain amount.