Effect of tetragonal distortion introduced by anti-site defect configuration on additional hardening in off-stoichiometric Al-rich Ni 3Al alloys

Seiji Miura, Satoshi Takizawa, Tomoo Suzuki, Yoshinao Mishima, Tetsuo Mohri

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

A theoretical approach to the hardening mechanism of L12-Ni 3Al compound with Al-rich off-stoichiometric composition is attempted based on the classical elastic interaction model between an edge dislocation and a unit cell with an equi-atomic composition embedded in Ni3Al. A tetragonal distortion is expected to arise from a local anisotropic atomic configuration in the unit cell which is recognized as a face-centered tetragonal-L10 or distorted B2 NiAl structure around an anti-site Al atom. According to the study by Cochardt et al. (Acta Metall 1955;3:533), it is found that the maximum point force Fm on an edge dislocation from the local L10 unit cell increases with decreasing the c i/ai ratio of the L10 structure toward the stable B2 structure, which is expected from the authors' recent electronic structure calculations on the stability of L10-NiAl relative to B2-NiAl. This increment of Fm by decreasing the ci/a i ratio accounts for a larger hardening in Al-rich Ni3Al than that in Ni-rich Ni3Al at 77 K.

Original languageEnglish
Pages (from-to)5175-5181
Number of pages7
JournalActa Materialia
Volume53
Issue number19
DOIs
Publication statusPublished - 2005 Nov 1

Keywords

  • Microstructure mechanical properties
  • NiAl aluminides
  • Phase diagram

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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