The Effect of Sintering on the Structure and Hardness of Mechanically Alloyed Cu-Zr Alloys

Age-hardenable Cu-Zr alloys are used in electrical and thermal conductive elements such as resistance welding electrodes. In the present study, mixtures of pure copper and zirconium powders in 1, 3 and 6 weight percents of Zr were milled for four differenthours. As milled powder mixtures were subsequently cold-pressed and followed by sintering at 450, 600 and 750°C. Vickers microhardness measurements were performed on as milled and sintered samples. Resulted microstructures were studied by opticalmicroscopy. Results showed that hardness in samples increased by milling time. Recovery and recrystallization processes are much slower in samples with higher Zr-contents and in those milled for longer times. These observations were attributed to the interactions of solute Zr atoms and also precipitated Zr-riched particles with recovery and recrystallization processes.