Elastic properties of grain boundaries influenced the macroscopic behavior of materials such as their resistance to deformation but had proved extremely difficult to measure experimentally. Conventional techniques for studying elastic properties of materials could only provide a macroscopic (grains + boundaries) average response. Here, local strain measurements using geometric phase analysis were carried out in ultrafine grained copper on twin boundaries containing dislocations. Experimental results and simulations using isotropic elasticity revealed an easier deformability of the boundary compared to the matrix. Enrichment of the boundaries in dislocations during deformation seemed to eliminate this effect by mutual cancelling of the strain fields from adjacent dislocations.

Local Strain Analysis in Twin Boundaries in Ultrafine Grained Copper. M.Sennour, S.Lartigue-Korinek, Y.Champion, M.J.Hÿtch: Journal of Materials Science, 2008, 43[11], 3806-11