Atomic ordering in binary <i>A</i>l5-type phases

Abstract

Abstract : The degree of long-range order has been determined for 20 binary A15-type phases containing various transition elements. A tendency toward a lower degree of order was noted as the component elements were chosen successively from columns in the periodic table approaching the Mn column. A comparison of the ordering in the A15-type phases with the ordering previously reported for various binary sigma phases suggests that the remarkable stability of these phases may result from an interdependence between the electronic structure and the ability of the atoms to undergo deformations in conforming to geometrical packing requirements. (Author)