Effect of cold-working and aging processes on the microstructure, mechanical properties and electrical conductivity of Cu–13.5%Mn–4%Ni–1.2%Ti alloy

Abstract

In this study, variations of hardness, electrical conductivity, strength, elongation and microstructure of the Cu–13.5%Mn–4%Ni–1.2%Ti alloy were investigated during aging, cold-working and subsequent aging. X-ray diffraction (XRD), transmission electron microscopy and scanning electron microscopy methods were used to evaluate the microstructure of the alloy. Tensile, hardness and electrical conductivity measurements were also used for investigating the effects of processing parameters on the characteristic of the alloy. Hardness value of 190HV and strength of 644MPa were obtained after aging the as-cast alloy for 4h at the temperature of 500°C. The maximum hardness and strength increased up to 253HV and 816MPa, respectively, after aging 60% cold-worked samples for 1h at the temperature of 500°C. The dominant strengthening mechanism during aging was attributed to the precipitation of Cu4Ti phase. Formation of the β-Cu3Ti phase during aging at the temperature of 500°C was another reason of strengthening. As a result of aging, electrical conductivity of both as-cast and cold-worked alloys was improved. The maximum conductivity of 29.7% IACS was attained after aging the as-cast material at the temperature of 500°C for 4h.