Nanoclusters first: a hierarchical phase transformation in a novel Mg alloy.

摘要: The Mg-Y-Zn ternary alloy system contains a series of novel structures known as long-period stacking ordered (LPSO) structures. formation process and its key concept from viewpoint phase transition are not yet clear. current study reveals that the transformation is traditional spinodal decomposition or structural but, rather hierarchical transformation. In this transformation, clustering occurs first, spatial rearrangement clusters induce secondary eventually lead to two-dimensional ordering clusters. was examined using in situ synchrotron radiation small-angle X-ray scattering (SAXS). Rapid quenching liquid into thin ribbons yielded strongly supersaturated amorphous samples. samples were heated at constant rate 10 K/min. patterns acquired. SAXS analysis indicated small grew sizes 0.2 nm after they crystallized. distributed randomly space transformed microstructure with two well-defined cluster-cluster distances, one for segregation periodicity LPSO other in-plane segregated layer. This structure concomitantly introduces periodical fault required 18R