Microstructure and mechanical properties of liquid–phase sintered W@NiFe composite powders

Abstract

W–Ni–Fe heavy alloys were obtained by liquid–phase sintering of W@NiFe composite powders. The face–centered cubic NiFe alloys were deposited as a shell on the core of tungsten particle to form W@NiFe composite powders by intermittently electrodeposition. After liquid–phase sintering, W–Ni–Fe heavy alloys had more gradient morphology and shape distortion as the holding time increased. The bending strength and hardness distributed graded at 1470 °C holding for 0.5 h. Top layer of gradient W–Ni–Fe heavy alloys at 1470 °C holding for 0.5 h showed low WW contiguity, no normal growth of W particle size and high sintered density, which led to excellent bending strength (1245 MPa) and hardness (340 HV0.2). The structure and composition of W@NiFe composite powders and the optimization of sintering process parameters were analyzed and discussed. The sintering behavior of W@NiFe composite powders were also investigated in details.