Effects of cold work on precipitation hardening of Cu-4.5 mass% Ti alloy

Abstract

The structure and properties of a solution treated, cold worked and aged Cu-4.5%Ti alloy were studied by means of optical, scanning and transmission electron microscopy as well as hardness, tensile tests and electrical conductivity measurements. Prior cold work (rolling) increases the peak hardness from 340 to 425 VHN, the tensile strength from 890 to 1380 MPa and the conductivity from 10 to 25% IACS on aging the alloy in the temperature range from 400 to 450°C. Maximum strengthening of the alloy is attributed to the precipitation of a coherent, metastable β′ phase (Cu4Ti). The alloy is deformed through profuse twinning. The ductile mode of fracture of the aged alloy is not affected by the prior cold work.