Microstructure Evolution in Mg_98.6Y₁Zn_0.4 Alloys and the Development by Hot Deformation Examined by Synchrotron Radiation Small- and Wide-Angle Scattering

Abstract

Synchrotron radiation small- and wide-angle scattering measurements have been performed for Mg_98.6–Y₁–Zn_0.4 alloys. In the early stage of phase transformation from supersaturated solid solutions, isotropic scattering suggesting segregation at grain boundaries was observed. It grew with temperature during heating the sample at a constant rate of 0.133 K/s. Above 600 K where introduction of stacking faults is expected, needle-like scattering became visible, which represents platelet shape segregation of cluster layers called cluster arranged layer (CAL). The layer eventually developed to form multiple layers, cluster arranged nano plates (CANaP) at higher temperatures. Microstructure change by hot rolling after the heat treatments has been examined from a viewpoint of kink-deformed microstructures.

Fig. 6 SAXS patterns from the samples hot-rolled after heat treatment, compared with the undeformed one (a). SAXS patterns with the incident beam parallel to the transverse direction (b), (d) and rolling direction (c), (e) are shown. Thickening of the CALs was observed after hot rolling. Triangles at q ∼5 nm⁻¹ are the peak positions of diffuse scattering by in-plane ordering of L1₂ clusters.