ORIGINAL ARTICLE

The International Journal of Advanced Manufacturing Technology

, Volume 67, Issue 9, pp 2233-2242

Microstructural evolvement and formation of selective laser melting W–Ni–Cu composite powder

  • Danqing ZhangAffiliated withSchool of Mechanical and Aerospace Engineering, Nanyang Technological University
  • , Qizhou CaiAffiliated withState Key Laboratory of Material Processing and Die and Mould Technology, Huazhong University of Science and Technology Email author 
  • , Jinhui LiuAffiliated withHeilongjiang Institute of Science and Technology
  • , Jian HeAffiliated withState Key Laboratory of Material Processing and Die and Mould Technology, Huazhong University of Science and Technology
  • , Ruidi LiAffiliated withState Key Laboratory of Material Processing and Die and Mould Technology, Huazhong University of Science and Technology

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Abstract

W–Ni–Cu alloy (90 wt% W, 7.5 wt% Ni, and 2.5 wt% Cu) parts were successfully fabricated via selective laser melting method. Phases, microstructure, compositions, and laser forming parameters of laser melted samples were investigated. It was found that the W–Ni–Cu powder system was based on the mechanism of liquid solidification. This process was realized through full melting of W, Ni, and Cu particles under high laser energy input. However, using relatively lower energy input, particle bonding was realized through liquid phase sintering with complete melting of Ni–Cu acting as binder and nonmelting of W acting as structure. Due to the Ni–Cu solid solution phase that appeared in a wide range from 1,084 to 1,455 °C, a coherent matrix interface can be observed after solidification. The microhardness of laser-fabricated specimens varied with different powder layer thicknesses, resulting from the laser-treated condition and ability of trapped air in the loose powder bed to escape. The metallurgical mechanisms were also addressed.

Keywords

Selective laser melting W–Ni–Cu alloy Process window Microstructure