Transformation of Hume-Rothery phases under the action of high pressure torsion

It has been revealed experimentally that high-pressure torsion induces phase transformations of certain Hume-Rothery phases (electron compounds) to others. High-pressure torsion induces the $\zeta\to\delta+\varepsilon$ reaction in copper-tin alloys with the appearance of the $\delta+\varepsilon$ phase mixture as after long-term annealing in the temperature range $T_{\text{eff}}=(589{-}641)\,^\circ$C. The mass transfer rate driven by high-pressure torsion is 14–18 orders of magnitude higher than the rate of conventional thermal diffusion at the processing temperature $T_{\text{HPT}}$. This phenomenon can be explained by an increased concentration of defects (in particular, vacancies) in the steady state under high-pressure torsion, which is equivalent to an increase in the temperature.