Bulk and Defect Properties of Ordered Intermetallics: A First-Principles Total-Energy Investigation

摘要: First-principles quantum mechanical calculations based on local-density-functional theory have been used to investigate the fundamental factors that govern deformation and fracture behavior of ordered intermetallic alloys. Unlike in Ni[sub 3]Al, calculated elastic constants shear fault energies indicate anomalous yield strength is not likely occur 3]Si. From Griffith a phenomenological relating toughness ideal cleavage strength, 3]Si predicted be ductile with respect fracture. For TiAl, we find absence structural vacancies due strong Ti-Al bonding similar atomic radii for Ti Al. NiAl, defect structure found dominated by two types defects - monovacancies Ni sites substitutional antisite Al sites. FeAl, other hand, more complex structure, which closely related importance electronic effect FeAl. More importantly, predict tendency vacancy clustering FeAl large binding energy divacancies. Effects thermomechanical history microhardness are discussed terms results.