In thiswork we present the development of a method for the prediciton of finite temperature
elastic and thermodynamic properties of cubic, non-magnetic unary and binary metals
from first principles calculations. Vibrational, electronic and anharmonic contributions to
the free energy are accounted for while magnetic effects are neglected. The method involves
the construction of a free energy surface in volume/temperature space through the use of
quasi-harmonic lattice dynamics. Additional strain energy calculations are performed and
fit to the derived thermal expansion to present the temperature dependence of single crystal
elastic constants. The methods are developed within the framework of density functional
theory, lattice dynamics, and finite elasticity. The model is first developed for FCC aluminum
and BCC tungsten which demonstrate the validity of the model as well as some of
the limitations arising from the approximations made such as the effects of intrinsic anharmonicity.
The same procedure is then applied to the B2 systems NiAl, RuAl and IrAl which
are considred for high temperature applications. Overall there is excellent correlation between
the calculated properties and experimentally tabulated values. Dynamic methods for
the prediction of temperature dependent properties are also introduced and a groundwork
is laid for future development of a robust method.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2779 |
| Date | 15 May 2009 |
| Creators | Williams, Michael Eric |
| Contributors | Arroyave, Raymundo |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | electronic, application/pdf, born digital |
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