Heterogeneous microstructure and deformation behavior of an automotive grade aluminum alloy

Aluminum alloy is today considered as a prime selection for manufacturing lightweight structural components in the automotive industry to increase fuel efficiency and reduce harmful emissions. The aim of this study was to identify the effect of microstructure and strain rate on the tensile deformation behavior of a high-pressure die-cast Silafont*-36 alloy, with special attention to strain hardening behavior and deformation mechanisms. The alloy consisted of randomly oriented primary alpha-Al phase and Al-Si eutectic structure in a form of heterogeneous microstructures, with Sr-modified Si particles exhibiting a coral-like fibrous network. The local misorientations in most primary alpha-Al grains was below 1 degrees, suggesting strain-free grains along with some extent of near-boundary residual strains due to the thermal mismatch between aluminum and silicon. A superior strength-ductility combination was achieved, along with enhanced Young's modulus and quality index owing to the unique heterogeneous microstructures. The cast alloy exhibited a smooth deformation characteristic with good coordination deformation and strong strain hardening capacity. Strain hardening exponents evaluated via the equations proposed by Ludwik, Hollomon, Swift, and Afrin et al., respectively, showed basically the absence of strain-rate effect from 1 x 10(-5) to 1 x 10(-2) s(-1). During the tensile deformation, crack initiated from the sample surface and propagated through the alternate microconstituents of softer primary alpha-Al phase and harder eutectic structure. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Aluminum alloy is widely used in the automotive industry for its lightweight and high-performance characteristics. This study focused on the microstructure and strain rate effects on the tensile deformation behavior of a high-pressure die-cast Silafont*-36 alloy, revealing unique heterogeneous microstructures and strain hardening behavior.