Determination of site occupancy of additives X (X=V, Mo, W and Ti) in the Nb–Cr–X Laves phase by ALCHEMI

Abstract

Atom location by channelling enhanced microanalysis (ALCHEMI) was carried out to investigate the site occupancy of additives X (X=V, Mo, W and Ti) in the Nb–Cr–X Laves phase. In order to make clear the detailed substitutional behavior of the additives, specimens with different compositions were prepared for each system. In the C15 structure of the Laves phase, fairly strong electron channelling effects were observed under two planar channelling conditions where the incident electron beams were nearly parallel to the (400) and (220) planes. It was shown that V prefers the Cr site, while Mo, W and Ti preferentially occupy the Nb site.