Nanostructure Distribution and Strengthening Mechanisms in the Interface Regions of Al–Zn/Al–Mg Multilayered Composites

Abstract

In this study, we examined the distribution of nanostructures in the interdiffusion layer of Al–Mg/Al–Zn/Al–Mg multilayer composites with different layer width via microbeam small-angle X-ray scattering (SAXS) measurements and direct observation using transmission electron microscopy (TEM). The changes in scattering profiles across the graded interfacial layers reflected the spatial change in the volume fraction, average size of precipitates, and their distribution in the sample. Microstructural parameters obtained from the SAXS analysis were used to explain the local hardness change in the interface area. Within the single interdiffusion layer of Al–Zn–Mg alloy, both of the Orowan and cut-through mechanisms were observed. TEM imaging was used with the same projection of SAXS to analyze the various shapes of the precipitates to explain the anisotropy in the 2-dimensional scattered intensity measured via SAXS. The present results revealed the spatial distribution of nanostructures with averaged parameters and explained the local mechanical properties within the interface region of the multilayer composite sheets.

Fig. 7 (b) Plots of different strengthening mechanisms on the specimen after aged at 393 K for 5 min, 3 h. Distribution of Mg is not shown.