Composition and structure variations during mechanical alloying to produce the intermetallic Cr2Nb

Abstract

The evolution of the mechanical alloying process by ball-milling elemental chromium and niobium powders has been studied as a function of milling time. Evaluation of the layered structure of the alloyed powders by energy dispersive spectroscopy and X-ray analysis has been made. Although the Cr2Nb hexagonal phase forms after 15 h milling time, when much of the powder presents the equilibrium range of composition, further milling to 25 h produces the disappearance of this phase. This behaviour is explained in terms of chemical disorder induced by the deformation process such that structure stability is not possible when a high degree of order is required.