Metallurgical and Materials Transactions A

, Volume 29, Issue 7, pp 1911–1915 | Cite as

Effect of Ni on vacancy concentrations and hardness in FeAl alloys

  • L. M. Pike
  • Y. A. Chang
Article

Abstract

The effects of nickel additions to iron aluminides are investigated with respect to vacancy concentrations and solid-solution hardening. Lattice parameters, densities, vacancy concentrations, and hardnesses were measured for FeAl alloys (40, 45, 48, 50, and 51 at. pct Al) with up to 12 at. pct Ni additions, as quenched at both 700 °C and 1000 °C. It is found that Ni does not prevent the elimination of thermal vacancies, as has been suggested in previous studies. However, the equilibrium vacancy concentrations are affected by the Ni additions. No clear evidence of solid-solution hardening by the Ni additions themselves was found. Instead, it appears that the role of Ni in hardening FeAl is through the effect the Ni has on the vacancy concentration. It was found that the hardness of most of the Ni-containing FeAl alloys could be directly correlated to the square root of the vacancy concentration.

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Copyright information

© ASM International & TMS-The Minerals, Metals and Materials Society 1998

Authors and Affiliations

  • L. M. Pike
    • 1
  • Y. A. Chang
    • 2
  1. 1.the Metals and Ceramics DivisionOak Ridge National LaboratoryOak Ridge
  2. 2.the Department of Materials Science and EngineeringUniversity of WisconsinMadison

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