Some structural effects of plastic deformation on tungsten heavy metal alloys

Tungsten-based heavy metal alloys containing 90–97% W are two-phase composites combining high density, high strength and relatively high ductility. W content and manufacturing parameters have a strong influence on the deformation and fracture behavior of the alloys. Specimens with different content of W were prepared. The microstructure was studied after successive stages of plastic deformation, allowing the delineation of the weak regions of importance as fracture starting points. It was confirmed that the material plasticity increases substantially with decreasing tungsten content and that the deformation capability is determined by the condition of the W–W and W–matrix zone interfaces which is different at the compression and tension modes of deformation. A correlation between microstructure and mechanical properties was found and an explanation for the improved plasticity with lower tungsten content is given.