Abstract:CuCrZr alloys were treated with the thermal stretch process at various temperatures from 100 to 300 °C. The results reveal that the thermal stretch process is successfully developed to manufacture the precipitation hardening CuCrZr alloys with a good combination of microhardness and electrical conductivity. By increasing the tensile elongations at each temperature from 100 to 300 °C, the microhardness increases whereas the electrical conductivity decreases slightly. Cr-containing precipitate phases with a Nishiyama–Wasserman orientation relationship to the copper matrix were observed by TEM. The achievement of high micro-hardness and acceptable electrical conductivity in the thermal stretch treated alloys is ascribed to the interactions of the heteroatom solution, dislocation increment, grain refinement and dispersive precipitation effect.

Key words: CuCrZr alloys; thermal stretch treatment; microhardness; electrical conductivity