Effect of Ni:Si ratio on microstructure and properties of powder metallurgical Corson alloy

Abstract

In this study, powder metallurgical Cu-Ni-Si alloys with different Ni:Si ratios are produced by cold pressing sintering (600 MPa, at 950°C for 60 min) and bulk materials are solution annealed at 950°C for 60 min, quenched in water and aged at 450°C for 60 min. A fine distribution of Ni-Si compounds embedded in a netted-free structure is formed in the matrix. Although a conductivity level of at least 22% IACS is achieved in all powder metallurgical alloys, the impurity effect is dominant and a decrease in the conductivity is detected by increasing Ni:Si ratio. However, a slight increase in electrical conductivity is achieved by the precipitation of nickel silicides in the α-Cu matrix under aging conditions. Increasing Ni:Si ratio directly increases the hardness of the powder metallurgical matrix, and a hardness value of 73 HV0.1 is obtained for the aged alloy having the highest Ni:Si (5:1) ratio.

Keywords

• corson alloy
• powder metallurgy
• conductivity
• hardness