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Title: Point defect concentrations and solid solution hardening in NiAl with Fe additions

Technical Report ·
DOI:https://doi.org/10.2172/537325· OSTI ID:537325
;  [1];  [2]
  1. Univ. of Wisconsin, Madison, WI (United States). Dept. of Materials Science and Engineering
  2. Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

The solid solution hardening behavior exhibited when Fe is added to NiAl is investigated. This is an interesting problem to consider since the ternary Fe additions may choose to occupy either the Ni or the Al sublattice, affecting the hardness at differing rates. Moreover, the addition of Fe may affect the concentrations of other point defects such as vacancies and Ni anti-sites. As a result, unusual effects ranging from rapid hardening to solid solution softening are observed. Alloys with varying amounts of Fe were prepared in Ni-rich (40 at. % Al) and stoichiometric (50 at. % Al) compositions. Vacancy concentrations were measured using lattice parameter and density measurements. The site occupancy of Fe was determined using ALCHEMI. Using these two techniques the site occupancies of all species could be uniquely determined. Significant differences in the defect concentrations as well as the hardening behavior were encountered between the Ni-rich and stoichiometric regimes.

Research Organization:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Organization:
USDOE Office of Energy Research, Washington, DC (United States)
DOE Contract Number:
AC05-96OR22464
OSTI ID:
537325
Report Number(s):
CONF-970909-2; ON: DE97007774; BR: KC 02 01 05 0; TRN: AHC29722%%90
Resource Relation:
Conference: 2. international symposium on structural intermetallics, Champion, PA (United States), 21-26 Sep 1997; Other Information: PBD: [1997]
Country of Publication:
United States
Language:
English