Point defects in binary NbCr 2 Laves-phase alloys

Abstract

Point defects in the binary NbCr{sub 2} alloys have been studied and clarified combining both bulk density and X-ray lattice parameter measurements. It was shown that the previous postulation that constitutional vacancy is the defect mechanism at the Nb-rich side is not accurate. The constitutional defects on both sides of stoichiometry for the NbCr{sub 2} system are of the anti-site type. Thermal vacancies exhibiting a maximum at the stoichiometric composition were obtained in samples quenched from 1,400 C. These could be completely eliminated by annealing at 1,000 C.