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 degrees C for 60 min) and bulk materials are solution annealed at 950 degrees C for 60 min, quenched in water and aged at 450 degrees 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 a-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.