2020 Volume 59 Issue 1 Pages 38-42
The Co was added to Cu–Ni–Si alloy containing 4〜6 wt％ Ni and 0.9〜1.5 wt％ Si, and the aging behavior was investigated. The hardness change of Cu–（6–x）Ni–xCo–1.5Si alloy aged at 500℃ showed that the time to peak aging was shifted toward to the fastest, and the maximum hardness was increased with increasing Co addition. However, the Co replacement was over the 1.9 wt％ in Cu–（6–x）Ni–xCo–1.5Si alloy, the hardness has overall low value. The discontinuously precipitated region was decreased with increasing Co substitution in Cu–4Ni–0.95Si and Cu–4.75Ni–1.13Si alloy after aging. The hardness and conductivity changes of Cu–（4–x）Ni–xCo–0.95Si and Cu–（4.75–x）Ni–xCo–1.13Si alloys revealed that the Co substituted Cu–4.75Ni–1.13Si alloy showed no sudden hardness drop during aging. The drawn Cu–3.99Ni–0.76Co–1.13Si alloy with 93.75％ area reduction has conductivity about 25％ IACS, but high tensile strength over 1100MPa. The Co substitution to Cu–Ni–Si alloy could suppress mechanically detrimental discontinuous precipitation and stabilize normal precipitation, and increase strength after drawing.
