Influence of Processing on the High Strain Rate Behavior of Refractory Metals - A Review

The high strain rate behavior of structural refractory metals such as tungsten, tantalum, hafnium and their alloys is reviewed. Tungsten, tantalum and their alloys exhibit significant rate sensitivity where as hafnium exhibits little or no rate sensitivity. Single crystal and textured tungsten in orientation are found to exhibit excellent ductility whereas in orientation they fail in a typically brittle manner. Tungsten heavy alloys (WHA) show moderate ductility and are also found to exhibit strain localization at high strain rates. Tantalum and their alloys exhibit moderate to excellent ductility but their deformation is highly dependent on initial processing texture. Hafnium exhibits excellent ductility and is prone to localization in a wide range of strain rates. The macroscopic high strain rate behavior of refractory metals is explained in terms of the processing conditions to which they are subjected and the resulting microstructure