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

• Horie Hiroyasu

  Kurami Branch, Technology Development Center, JX Nippon Mining & Metals Corporation

• Kammuri Kazuki

  Kurami Branch, Technology Development Center, JX Nippon Mining & Metals Corporation

• Imozuka Yuki

  Division of Mechanical Science and Engineering, Graduate School of Natural Science and Technology, Kanazawa University

• Tsuji Yumemaru

  Division of Mechanical Science and Engineering, Graduate School of Natural Science and Technology, Kanazawa University

• Watanabe Chihiro

  Faculty of Mechanical Engineering, Institute of Science and Engineering, Kanazawa University

Abstract

The effects of Co and P on the discontinuous precipitation (DP) behavior of Cu–Ni–Si system alloys have been investigated using Cu–4.5 mass%Ni–1.1 mass%Si alloy (base alloy), Cu–4.0 mass%Ni–0.5 mass%Co–1.1 mass%Si alloy (Co alloy) and Cu–4.0 mass%Ni–0.5 mass%Co–1.1 mass%Si–0.05 mass%P alloy (Co + P alloy) aged at 430, 460 and 490°C. In all the alloys, slightly before attaining peak age-hardening 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⁻¹, 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⁻¹. 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 δ precipitates than that of base one, which successively suppressed the boundary migration.   This Paper was Originally Published in Japanese in Journal of the Japan Institute of Copper 57 (2018) 101–106.

Journal

• MATERIALS TRANSACTIONS

  MATERIALS TRANSACTIONS 61 (4), 663-667, 2020-04-01

  The Japan Institute of Metals and Materials

Keywords

• copper–nickel–silicon system alloy
• discontinuous precipitation
• substitution of cobalt
• addition of phosphorus

Details

• CRID: 1390565134840116480
• NII Article ID: 130007815395
• NII Book ID: AA1151294X
• DOI: 10.2320/matertrans.mt-m2019152
• ISSN: 13475320
• ISSN: 13459678
• NDL BIB ID: 030344680
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I030344680
• Web Site: https://www.jstage.jst.go.jp/article/matertrans/61/4/61_MT-M2019152/_pdf
• Text Lang: en
• Data Source:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed