Effect of friction stir processing on microstructure, texture, and mechanical properties of AA7075T7352 alloy

Abstract

The friction stir processing (FSP) of AA7075T7352 alloy raises the temperature, partially dissolves the metastable ɳꞌ, ɳ, and Al2CuMg intermetallics, but precipitates Al23CuFe4 and Al2Cu phases. High-density dislocations are partially recovered and grains in the nugget zone (NZ) are refined by dynamic recrystallization (DRX). The intensity of deformation texture is decreased, though the compressive residual stress is increased. Strengthening in the FSPed AA7075T7352 alloy arises mainly due to the Orowan mechanism followed by solid solution, dislocations and grain boundary. Partial dissolution of precipitates and reduction in dislocation density, reduce strength but incorporation of compressive residual stress, refined grain size, and increased co-incident site lattice (Σ3) boundaries improve the ductility which in turn increases work-hardening ability. The FSPed AA7075T7352 alloy follows the Swift flow behavior, and the material fails by the mixed modes of ductile-brittle fracture. The potentiodynamic corrosion rate of FSP processed alloy is decreased due to reduction in size, volume fraction, and interspacing of ɳ precipitates dispersed in the matrix but the severity of stress corrosion cracking is increased because of reduced spacing and size of it in grain boundary. © 2025 Elsevier B.V.