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Abstract

Nano- and micromechanical experiments have been recently used to study material behavior at those scales. Nanoindentation is a common method for characterizing the material properties but the induced strain field includes strain gradients, which make material property identification troublesome. More recently, compression experiments on nano- and micropillars have been used because of the homogeneous strain field in the pillars. These experiments showed that localized plasticity occurs in avalanches. However, the precise correlation is difficult due to the possibility of multiple slip systems with different Schmidt factors, and multiple parallel slip planes. To reduce these complexities, we introduce a micro-shear experiments on pure copper using a double shear geometry. Using the focused ion beam technique, a micro-shear specimen was machined which promotes (1-11)[101] slip. Comparing SEM images before and after deformation provide evidence for localized shear on the(1-11)[101] slip direction. Load-displacement data identify a load plateau, which is the stress at which a dislocation avalange is triggered which leads to localized plasticity. From the stress, a activation stress of dislocation nucleation and propargation in copper is identified.