Free energy simulation of grain boundary segregation and thermodynamics in Ni sub 3-x Al sub 1+x

Conference · Mon Jan 01 04:00:00 EST 1990

OSTI ID:6265732

Najafabadi, R; Wang, H Y; Srolovitz, D J ^[1]; LeSar, R ^[2]

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1. Michigan Univ., Ann Arbor, MI (USA). Dept. of Materials Science and Engineering
2. Los Alamos National Lab., NM (USA)

The free energy simulation method is employed to study segregation to {Sigma}5 and {Sigma}13 (001) twist grain boundaries and their free energies in ordered Ni{sub 3-x}Al{sub 1+x}. In the temperature range studied (300--900K), it is shown that there is almost no segregation, strong Al segregation, and weak Ni segregation to the grain boundary for the stoichiometric, Al-rich, and Ni-rich bulk compositions respectively. It is also shown that the segregation is limited to a few (002) planes around the grain boundary and its magnitude decreases with increasing temperature. For Al-rich bulk composition, it is demonstrated that segregation at low temperature substantially lowers the grain boundary free energy. 8 refs., 7 figs.

• Research Organization: Los Alamos National Lab., NM (USA)
• Sponsoring Organization: DOE/ER
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 6265732
• Report Number(s): LA-UR-91-276; CONF-901105--90; ON: DE91007473
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
ALLOYS
ALUMINIUM ALLOYS
CRYSTAL STRUCTURE
ENERGY
FREE ENERGY
GRAIN BOUNDARIES
HIGH TEMPERATURE
INTERMETALLIC COMPOUNDS
MICROSTRUCTURE
NICKEL ALLOYS
NICKEL BASE ALLOYS
PHYSICAL PROPERTIES
SEGREGATION
THERMODYNAMIC PROPERTIES