Combining nanoindentation and Bragg coherent diffraction imaging to investigate small-scale plasticity

Abstract

The mechanical properties of materials at the nanoscale are still poorly understood, despite intensive research efforts, in particular because mechanical tests are blind to the detailed microstructure of the samples. The latter is however crucial at small scales, when stochastic response dominates the initial elasto-plastic transition. To extract a comprehensive mechanical behavior at this scale, and despite this stochastic aspect, studying a large population of nano-objects is necessary. Additionally, investigating the early stage of the plasticity, correlated with the initial microstructure of the nano-objects, is essential. In this regard, we use a statistical approach to extract deterministic laws from various techniques such as nano-compression or nanoindentation, and we discuss the results in light with Bragg coherent diffraction imaging (BCDI) which provides the detailed crystalline state of the sample before and after mechanical testing. This ex situ approach is able to provide a more complete description of plastic behavior at small and large strains.