Effect of Co and P on the Discontinuous Precipitation Behavior in High Concentration Corson Alloy

Abstract

The effects of Co and P on the discontinuous precipitation (DP) behavior of CuNiSi system alloys have been investigated using Cu4.5 mass%Ni1.1 mass%Si alloy (base alloy), Cu4.0 mass%Ni0.5 mass%Co1.1 mass%Si alloy (Co alloy) and Cu4.0 mass%Ni 0.5 mass%Co1.1 mass%Si0.05 mass%P alloy (Co + P alloy) aged at 430, 460 and 490°C. In all the alloys, slightly before attaining peak agehardening within grains, DP cells nucleated at grain boundaries and grew into the grains ahead of reaction fronts. The growth rates of DP cell for Co alloy were slower than those for Base one. Moreover, the trace addition of P to Co alloy (Co + P alloy) considerably retarded DP reaction. The kinetic analyses of DP using the Turnbull (T) and Petermann and Hornbogen (P-H) models yielded grain-boundary diffusion data. The activation energies for the base and Co alloys obtained using the T model were nearly identical and 125 and 124 kJ mol ¹1 , respectively. The values for both alloys determined from the P-H model were slightly larger than those obtained from the T model and about 130 kJ mol ¹1 . These results strongly suggested that the growth of DP cells in base and Co alloys was controlled by the boundary diffusion of Ni, and Ni or Co in Cu matrix, respectively. The smaller growth rate of DP cells in the Co alloy was ascribed to the higher number density of continuous ¤ precipitates than that of base one, which successively suppressed the boundary migration. [

The Precipitation Behavior of a Cu-Ni-Si Alloy with Cr Addition Prepared by Heating-Cooling Combined Mold (HCCM) Continuous Casting

“…Many attempts have been tried for the further improvement in the electrical and mechanical properties of Cu-Ni-Si alloys by the addition of the third trace elements such as Cr, Co, Mg, Al and P to Cu-Ni-Si alloys [9][10][11][12][13]. Thereafter, the effects of these alloying elements on the properties and structure of Cu-Ni-Si alloys have been studied in many previous works [14][15][16]. Trace amount of P can form the Ni 3 P precipitates and suppress the discontinuous precipitation reaction, resulting in enhancement of both strength and elongation [17].…”

Recent Development of Joining and Conductive Materials for Electronic Components

“…Alloying is one of the measures to increase strength. It was reported that CuNi Si alloy with the addition of Co and P has high strength due to the discontinuous precipitation after aging treatment 123) and that CuTi alloy with the addition of Mg has higher strength and elongation than CuTi alloy. 124) Also, the treatment of cold-sprayed pure Al substrate and Cu-clad Al wire causes mutual diffusion forming a reaction layer and A d v a n c e V i e w increasing the strength.…”