The aging characteristics of Cu-Be-Sn alloy and the effect of additional elements

The aging characteristics and the corrosion resistance of Cu-Be and Cu-Be(1%)-Sn(4.5%) alloys were studied. The results obtained were as follows:(1) The transition temperature from the two-stage hardening to the high temperature age hardening of Cu-Be binary alloys increased with increasing Be content. (2) The ripples of Cu-Be alloys were observed especially clearer under the optical microscope on the process of both the two-stage hardening and the two-step aging. (3) The addition of Sn to Cu-Be(1%) binary alloy improved the age-hardenability. The transition temperature increased with increasing Sn content. (4) The addition of Fe, Co, Ni, Cr or Ti to Cu-Be(1%)-Sn(4.5%) retarded the discontinuous precipitation at grain boundaries, while the addition of Mn, Zn or Cd neither retarded nor accelerated. Especially the addition of Co was very effective. (5) By the addition of Sn, the corrosion weight loss of Cu-Be(1%)-Sn systems decreased in 5%HNO3 solution but increased in 5%HCl solution. The corrosion weight loss of Cu-Be(1%)-Sn(4.5%) increased in 5%HNO3 solution by the addition of Ti, Mn or Zn.