Grain Boundary Chemistry and Ductility in Ni-Base LI2 Intermetallic Compounds

Abstract

AbstractThe available experimental data for the Ni3X, LI2 intermetallics indicate a strong effect of chemistry on the tendency for brittle intergranular fracture. Combining the data for the binary compounds with the effects of macroalloying with × substituents and microalloying with boron, the resistance to intergranular fracture varies as Fe ~ Mn > Al ~ Ga > Si > Ge. Two models have been proposed to explain these chemistry effects. The basis for both models is that electronic charge localization is responsible for the brittle behavior of the ordered intermetallics. The models differ in the measure of charge redistribution; one uses valency differences whereas the other uses electronegativity differences.