Severe plastic deformation by high-pressure torsion of Hf and HfTi alloys

Abstract Hafnium and alloys of the hafnium‑titanium system were studied by X-ray diffraction analysis, scanning and transmission electron microscopy, as well as by measuring microhardness in the initial state and after severe plastic deformation by torsion under pressure of 4.5 GPa. It is established that the grain size is influenced by titanium content in the alloy, by degree of plastic deformation, and by the initial state of material. The smallest grain size is achieved in the alloy of equiatomic composition after its deformation in powder state.