Microstructural parameters and flow stress in Al-0.13% Mg deformed by ECAE processing

A high purity Al–0.13wt.% Mg alloy was deformed to a von Mises strain of 10 and subsequently annealed at temperatures between 100 and 400°C for 1h. Boundary spacings were measured in orthogonal directions for all boundaries by EBSD and their corresponding Sv were calculated over both measurement directions.

Boundaries with misorientations θ≥15° were used to calculate a standard Hall–Petch strengthening contribution while the boundaries with θ between 1° and 15° were used to calculate a dislocation strengthening contribution. The combined calculations showed close agreement to actual mechanical test data over more than two orders of magnitude of boundary spacing and significant morphology change.

The importance of measuring boundary misorientations for the determination of microstructure–property relationships is concluded.