New insights into single-grain mechanical behavior from temperature-dependent 3-D coherent X-ray diffraction

Abstract Coherent X-ray diffraction is able to yield non-destructively 3-D strain maps with unprecedented resolution in small isolated crystals. In this work we have used this technique to investigate the mechanical behavior of a single grain within a Au polycrystalline film. The 111 Bragg reflection from a 1250 × 950 × 475 nm single grain has been successfully measured in three dimensions during thermomechanical loading. From these 3-D reciprocal space maps the displacement field is obtained through a specific phase-retrieval procedure. The u z ( x , y , z ) component of the displacement field component is deduced as a function of temperature with a high spatial resolution of 17 × 17 × 22 nm within the single grain. This displacement field is discussed with respect to grain-to-grain interactions in the supported metal film. This study opens important perspectives for the evaluation of mechanical properties of polycrystals via coherent X-ray diffraction.