Fabrication of W-20 wt.%Cu alloys by powder injection molding

摘要

W-20 wt.% Cu balls were fabricated by powder injection molding using a binder system consisted of paraffin wax, high density polyethylene, ethylene vinyl acetate and stearic acid. By optimizing the injection molding parameters, defect-free green parts were obtained. A two-step debinding process was employed to extract the binders in the molded samples. All soluble ingredients of the binders in the green parts were extracted during solvent debinding, and the residual binders can be removed in thermal debinding. The debound W-Cu samples were sintered in H_2 atmosphere at temperatures ranging 1050-1150 ℃ for 2 h. It was shown that relative density of the sintered W-Cu samples increases from 87.37% of the theoretical to 95.58% as sintering temperature rises from 1050 ℃ to 1150 ℃. Microstructures of the molded, the debound and the sintered W-Cu samples were observed by scanning electron microscope, and the sintered W-Cu balls have fine and homogeneous microstructures. Maximum compressive strength of W-Cu balls with 8.5 mm diameter reaches 58 kN.