Re-examining the relation between fracture strain and yield stress in Al-Mg-Si alloys

A linear relationship between fracture strain, εf, and yield strength first observed by Lloyd (2003) in aluminum alloys is re-examined for age-hardenable AA6063. A breakdown in the relationship is observed if AA6063 is pre-strained prior to ageing. A linear relationship is recovered for εf versus dislocation initial inter-obstacle spacing, ℓ.