EOS, thermodynamic, and structural-mechanical properties of intermetallic compounds

摘要

This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). Several classes of binary intermetallic compounds have important potential application as high temperature structural materials because of their high melting temperature, low density, and high strength, but their use is limited by their poor low temperature ductility and fracture toughness. The goal of this project was to further the development of techniques for performing ab-initio calculations of the electronic, structural, and elastic properties of these materials in an investigation of the relation between structure, composition, and mechanical properties of intermetallics. Materials properties to be addressed in these calculations included the equation of state (EOS), defect structure energetics, and elastic constants and phonons. Major accomplishments included calculations of stacking fault and twin energies in layered TiAl, structural stability in binary and ternary Ti-Al-Nb compounds, and point defect energies and elastic moduli of Laves phase intermetallics.