Irradiation-Induced Nanoprecipitation in Ni-W Alloys

Jaeyel Lee, Calvin R. Lear, Xuan Zhang, Pascal Bellon, Robert S. Averback

Research output: Contribution to journalArticle

Abstract

The evolution of Ni-W alloy thin films subjected to Kr irradiation at room temperature and subsequent annealing at 1123 K (850 °C) was studied by X-ray diffraction and transmission electron microscopy. Irradiation resulted in significant increase in grain size, from ~20 nm in the as-grown state to over 300 nm after irradiation and annealing. The compositions selected for the study, 18 and 23 at. pct W, resulted in the formation of an ordered Ni4W matrix after annealing. Remarkably, in the Ni-23 at. pct W films, irradiation followed by annealing induced the precipitation of two families of Ni2W4C carbides, large blocky ones at grain boundaries, and intragranular nanocarbides, ~5 to 20 nm in size and with a high number density, 9.0 × 1022m−3. In contrast, only blocky Ni6W6C carbides formed in control specimens directly subjected to annealing. The intragranular Ni2W4C nanocarbides displayed an orientation relationship with the Ni4W matrix, and they appear to be effective traps for implanted Kr ions, since nanobubbles formed on their periphery. The results suggest that non-equilibrium processing can be used to nucleate nanocarbides in the grain interiors of Ni-W alloys, and that this may improve alloy properties, including radiation resistance.

Original languageEnglish (US)
Pages (from-to)1046-1061
Number of pages16
JournalMetallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
Volume46
Issue number3
DOIs
StatePublished - Jan 1 2015

ASJC Scopus subject areas

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

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