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Residual stresses are well known to affect the fatigue, fracture and creep failure of metals; tensile stresses can contribute to driving crack growth whilst compressive stresses are inhibitive. Compressive surface stresses have been shown to influence toughness and crack path followed during fracture. Controlled plasticity burnishing allows concentrated regions of surface residual stress to be generated with a high degree of spatial resolution. This technique was applied to modified double cantilever beam specimens (mDCB) to provide discontinuous 1D residual stress fields. Investigations were conducted into the fracture behaviour of mDCB specimens with discrete burnished regions; CTOA measured using direct techniques has been used to characterise fracture toughness and observe its variation with stress field. Additionally, variations in the stress-strain relationship are monitored in conjunction with crack path stability. Results from this study demonstrate that direction of the residual stress field alters constraint levels and therefore fracture toughness and crack path stability.