Exploring the kink strengthening mechanism to enhance the mechanical response of mille-feuille structured Mg alloys by suppressing dynamic recrystallization

In this study, we explore the remarkable characteristics of kink strengthening in mille-feuille (MF) structured magnesium (Mg) alloys through a detailed investigation at the nanoscale. Our focus is on the MF-type Mg-0.4Zn-1.0Y (at%) alloy, which is distinguished by its complex hierarchical structure with hard cluster-arranged nano-scale plates having an average spacing of 18 nm and thickness of 1.3 nm. We examine the mechanical properties in relation to kink formation dynamics of extrudates specifically engineered to inhibit dynamic recrystallization (DRX). The yield strength of the MF-type Mg alloy is significantly enhanced, increasing from 115 MPa to 417 ± 2 MPa due to the DRX-suppressing extrusion process. Importantly, the microstructure of the extruded samples exhibits a high density of kink bands. Our analysis reveals a direct correlation between the dispersion of kink boundaries and the yield strength, providing new insights into the complex interactions within the material's microstructure and highlighting the remarkable potential of mille-feuille structured Mg alloys for advanced applications.