Aging Processes in Ultrafine-Grained Low-Alloyed Bronzes Subjected to Equal Channel Angular Pressing

The aging processes in Cu-0.7% Cr, Cu-0.9% Hf, and Cu-0.7% Cr-0.9% Hf alloys after equal channel angular pressing have been studied. ECAP leads to strong grain refinement (200 nm for Cu-0.7% Cr-0.9% Hf alloy). It was shown that the Cu5Hf particles are more efficient as strengthening phase than the particles of Cr-based solid solution. Alloying with hafnium also improves the thermal stability of hardening and minimizes recrystallization processes at aging temperatures. Temperature-time aging regimes of bronzes for achieving optimal combination of strength, ductility, and electrical conductivity were also determined. Ternary alloy after aging at 500 °C for 2.5 h has a tensile strength of 582 MPa, an elongation of 18%, and an electrical conductivity of 75% IACS.