Nanostructure and related mechanical properties of an Al-Mg-Si alloy processed by severe plastic deformation

TL;DR

This study investigates how high-pressure torsion processing refines the microstructure of an Al-Mg-Si alloy, significantly enhancing its strength through grain size reduction and element segregation.

Contribution

It demonstrates that severe plastic deformation produces a nanostructure with superior mechanical properties compared to traditional heat treatment.

Findings

Grain size refined to 100 nm

Yield stress doubled compared to T6 heat treatment

Massive segregation of alloying elements observed

Abstract

Microstructural features and mechanical properties of an Al-Mg-Si alloy processed by high-pressure torsion have been investigated using transmission electron microscopy, X-ray diffraction, three-dimensional atom probe, tensile tests and microhardness measurements. It is shown that HPT processing of the Al-Mg-Si alloy leads to a much stronger grain size refinement than of pure aluminium (down to 100 nm). Moreover, massive segregation of alloying elements along grain boundaries is observed. This nanostructure exhibits a yield stress even two times higher than that after a standard T6 heat treatment of the coarse grained alloy