Comparative analysis of the aging kinetics in low-alloyed Cu – Cr – Hf and Cu – Cr – Zr alloys after high pressure torsion

Abstract

The kinetics of phase precipitation during aging in the Cu – Cr – Hf and Cu – Cr – Zr alloys after high pressure torsion (HPT) has been studied and compared with quenching state. The effect of HPT on the kinetics of aging was revealed by the differential scanning calorimetry (DSC) and confirmed by changes in the microhardness and electrical resistivity. Analysis of the microstructure and phase precipitation after HPT and subsequent aging using a transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) revealed three types of phases in each of the alloys: Cu matrix, chromium and zirconium- or hafnium-rich phases. By measuring the microhardness, a higher degree hardening after HPT and subsequent aging was revealed in the Cu – Cr – Hf alloy compared to the Cu – Cr – Zr alloy.