Age-Induced Precipitating and Strengthening Behaviors in a Cu–Ni–Al Alloy

Satoshi Semboshi, Ryuta Hariki, Toshiya Shuto, Hiroshi Hyodo, Yasuyuki Kaneno, Naoya Masahashi

Research output: Contribution to journalArticlepeer-review

Abstract

Microstructural response and variations in strength and electrical conductivity of a Cu−20 at. pct Ni–6.7 at. pct Al alloy during isothermal aging at temperatures from 723 K to 1023 K (450 °C to 750 °C) were investigated to discuss the age-induced precipitation behavior and strengthening mechanism. At all aging temperatures, fine spherical γ′-Ni3Al particles were found to nucleate coherently with parent Cu grains by continuous precipitation and then grew gradually by Ostwald ripening. Domains with a high density of twins developed at grain boundaries during aging below 873 K (600 °C) followed by cellular components composed of fiber-shaped γ′-Ni3Al and Cu solid solution phases at the domain boundaries later. Both the domains and cellular components were suppressed at aging above 923 K (650 °C). The age-induced strengthening principally resulted from fine dispersion of γ′-Ni3Al coherent particles in the grains. The precipitation strengthening by the fine γ′-Ni3Al coherent particles exhibited a maximum at an aging temperature of 873 K (600 °C), resulting in excellent mechanical properties such as a high hardness of 340 ± 7 HV and an ultimate tensile strength of 980 ± 14 MPa, which are comparable to those of other commercial age-hardened Cu–Be, Cu–Ni–Si, and Cu–Ti alloys.

Original languageEnglish
Pages (from-to)4934-4945
Number of pages12
JournalMetallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
Volume52
Issue number11
DOIs
Publication statusPublished - 2021 Nov

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys

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