Significance of homologous temperature in softening behavior and grain size of pure metals processed by high-pressure torsion

► Metals with low melting points (In, Sn, Pb, Zn) were processed by high-pressure torsion (HPT). ► An unusual softening behavior was observed in these metals after processing by HPT. ► The hardness-strain behavior is represented by homologous temperature in HPTed metals. ► The steady-state grain size is significantly influenced by homologous temperature. ► The effect of stacking fault energy on grain size is minor at a given homologous temperature.