On the Correlation of the Hardness of B2 Compounds with Point Defect Concentrations

Abstract

AbstractPoint defects such as vacancies and anti-site atoms are known to strongly affect the mechanical properties of B2 compounds. The variations in the hardness of these compounds with composition and quenching temperature can often be correlated with the concentrations of these point defects. Simple themodynamic models using a quasi-chemical approach can be used to estimate the concentrations of point defects with composition and temperature. These estimates can often be supported by experimental methods. Knowledge of the concentrations of defects can then be compared to the variations in hardness using solid solution strengthening models. A consistent relationship is found for several B2 compounds. The hardening rates of vacancies are found to be greater than those of anti-site atoms. B2 compounds having the anti-structure defect structure (AuZn, FeCo) are investigated as well as those with the triple-defect structure (FeAl, NiAl, CoAl).