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

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 1250×950×4751250×950×475 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 uz(x,y,z)uz(x,y,z) component of the displacement field component is deduced as a function of temperature with a high spatial resolution of 17×17×2217×17×22 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.