X-ray diffraction can be used to study strain, piezoelectricity and heating in crystalline samples. Modern X-ray optics can reach below 100 nm focus size, which we have used to study core-shell [Wallentin 2017] and axially hetereostructured nanowires [Hammarberg 2020]. We have shown that the shape of bent nanowires can be reconstructed in 3D with nanometre precision [Wallentin 2017]. Hard X-rays can penetrate through thick samples, allowing measurements of operational devices [Wallentin 2016]. The intensity of focused X-rays can lead to beam damage, and we have studied beam induced heating of nanostructured samples [Wallander 2017]. We are also developing novel methods for coherent diffraction methods, which use phase retrieval to overcome the limit of the focusing optics. Recently, we showed how the uncontrolled rotation of 60 nm nanoparticles could be used for 3D strain imaging [Björling 2020].