Simple model of Mg2Al3: β and β' phases

Abstract

Two crystalline phases: β and β' of the Mg2Al 3 alloy are compared. There are three types of structural domains, whose structures are based on sets of hexagonal layers. The main chain contains 11 layers. It does not undergo any transformation during a phase transition from the β'-phase to the β-phase. Conversely, during this process, shorter chains vanish and transform into clusters, whose atomic positions are occupied partially. Any two adjoining domains merge in a coherent way. It does not apply to the third domain. At its border structural defects appear. They are the seeds of clusters emerging in the β-phase. © 2010 IOP Publishing Ltd.