Influence of Stoichiometry on the Strength of Nickel Beryllide

Abstract

ABSTRACTIt is demonstrated that the hardness of NiBe is dependant upon its stoichiometry; a minimum hardness is observed at the equiatomic composition. This behavior is similar to intermetallics that have the same crystallographic structure, e.g., NiAI and CoAl. The hardness increase for the off-stoichiometric compositions is a result of defect and anti-site defect structures, but may also, in part, be caused by interstitial oxygen. Nickel beryllides appear to have some intrinsic room temperature ductility, as evidenced by the absence of cracking near hardness indentations.