2023 Volume 62 Issue 1 Pages 251-256
Oxygen–free copper is an integral part of electric vehicles and renewable energy initiatives as the key conductor material owing to its high conductive properties. However, the poor heat resistance and poor stress relaxation resistance properties pose challenges for applications involving heat. This study aims to explore the potential for developing a new pure copper material with enhanced heat resistance and stress relaxation resistance properties while maintaining conductivity. Trace amounts of solute elements Mg, Sn, P, Ti, and Ag were added to oxygen–free copper, and the following results were obtained from the cold–rolled material：
(1) Mg, Sn, P, Ti, and Ag addition below 500 at ppm have little effect on yield strength.
(2) Mg and Ag addition below 200 at ppm have little effect on electrical conductivity.
(3) Mg and Sn addition above 100 at ppm increase the half softening temperature to over 300°C.
(4) Mg, Sn, and Ag addition above 100 at ppm increase the residual stress ratio to over 60%.
(5) Mg and Ag addition have superior balance among electrical conductivity, half softening temperature, and residual stress ratio, particularly, Mg addition of 100 to 200 at ppm exhibit excellent balance.
