On the origin of extremely high strength of ultrafine-grained Al alloys produced by severe plastic deformation

TL;DR

This paper investigates why ultrafine-grained aluminum alloys produced by severe plastic deformation exhibit exceptionally high strength, attributing it to ultrafine structure and solute segregation effects on dislocation behavior.

Contribution

It reveals the combined influence of ultrafine grain structure and solute segregation on the high strength of Al alloys, surpassing traditional Hall-Petch predictions.

Findings

Strength exceeds Hall-Petch predictions

Solute segregation affects dislocation mobility

Ultrafine structure enhances material strength

Abstract

Ultrafine-grained Al alloys produced by high pressure torsion are found to exhibit a very high strength, considerably exceeding the Hall-Petch predictions for the ultrafine grains. The phenomena can be attributed to the unique combination of ultrafine structure and deformation-induced segregations of solute elements along grain boundaries, which may affect the emission and mobility of intragranular dislocations.