Fine-grained 93W–5.6Ni–1.4Fe heavy alloys with enhanced performance prepared by spark plasma sintering

Abstract

Blended 93W–5.6Ni–1.4Fe powders were sintered via the spark plasma sintering (SPS) technique. Fine-grained 93W–5.6Ni–1.4Fe heavy alloys (W grain size is about 6µm) with liquid-phase sintered microstructure were obtained by control of the SPS process. After SPS, the alloys show relative density of 0.95 and tungsten–tungsten contiguity of 0.53. The alloys exhibit improved bending strength (about 1580MPa) and yield strength (about 1050MPa at room temperature and about 640MPa at 800°C), due to their fine-grained structure. The fracture morphology after bending test is mainly characterized as tungsten–tungsten intergranular rupture. A decreased tungsten–matrix interface decohesion is presented due to the improved binding strength of tungsten–matrix by “SPS effect”. The mechanical properties of SPSed 93W–5.6Ni–1.4Fe heavy alloys are dependent on the microstructural parameters such as tungsten grain size, matrix volume fraction and tungsten–tungsten contiguity.