Activation of unexpected slip systems in the interface affected zone in multilayered aluminum

Interface affected zones (IAZs), crucial for the excellent mechanical properties of multilayered metals, remains poorly understood at the early deformation stages. Here, a synchrotron-based polychromatic X-ray micro-diffraction technique was utilized to identify the IAZs in multilayered Al samples under a low tensile strain of 0.5%. The IAZs, characterized by high dislocation densities, were found to form by the activation of low Schmid-factor slip systems. The relationship between these anomalous slip systems and the complex multiaxial stress state is analysed, and their implications for mechanical properties is discussed. The findings advance the fundamental understandings of the constraint effects in multilayered structures.