Mechanisms of deformation and ductility in tungsten – A review

The physical, chemical, and mechanical properties of tungsten are at the far limits of all engineering materials. These unique properties, particularly ultra-high strength, density, and melting point, create enticing prospects for using tungsten in extreme engineering environments for nuclear, military and space applications. However, these environments also require materials that resist fracture, which presents a significant challenge for tungsten, particularly at low temperatures. This review discusses several significant factors that affect the ductile to brittle transition and low temperature ductility of tungsten. The effects of crystal structure, dislocation structure, and microstructure to describe competing factors in the plasticity and fracture of tungsten at low temperatures are assessed. In particular, the dislocation structure and the mechanisms of dislocation mobility are shown to be critical to understanding plasticity at low temperatures.