期刊
MATERIALS & DESIGN
卷 30, 期 6, 页码 2099-2107出版社
ELSEVIER SCI LTD
DOI: 10.1016/j.matdes.2008.08.036
关键词
Non-ferrous metals and alloys; Sintering; Microstructure
资金
- National Natural Science Foundation of China [50775113]
- Nanjing University of Aeronautics and Astronautics
Direct metal laser sintering (DMLS) was used to consolidate Cu-based alloy powder (Cu-10Sn and Cu-8.4P) reinforced with Ni particles. Phases, microstructures, compositions, and mechanical properties of laser-sintered part were studied. It showed that particle bonding was through a liquid phase sintering mechanism involving the complete melting of matrix alloy powder and the non-melting of cores of Ni reinforcing particles. A significant smoothening of Ni particles occurred in the liquid and the dissolved Ni element alloyed with Cu element to form CuNi solid solution, leading to a coherent particle/matrix interface after solidification. The dendrites of matrix alloys developed directionally and the primary dendritic spacing was highly refined to similar to 1.5 mu m, due to laser-induced super high temperature gradient and solidification rate. The additive P element acted as a localized deoxidizer to prevent the sintering system from oxidation by formation Of CuPO(3), thereby enhancing liquid-solid wettability and resultant sintering activity. A high densification level of 95.2% theoretical density was obtained after sintering. The fracture surface of laser-sintered part was mainly featured by a strong ductile type of fracture. The dynamic nanohardness of Ni reinforcing phase and Cu-based matrix alloys reached 1.82 GPa and 0.99-1.35 GPa, respectively. (C) 2008 Elsevier Ltd. All rights reserved.
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