In order to quantitative evaluation of micro strain which is close to the resolution of images, a novel evaluation method using three dimensional microstructure images is proposed in this study, especially for the purpose to use in-house micro-focused X-ray tomography apparatus with the resolution of 1-5 μm. The evaluation method is composed of two parts. One is a conventional calculation method to evaluate deformation and the other is a quantitative evaluation of error which is generated by apparatus resolution. By applying this method to NiMnGa/silicone composite under 5% compression strain, 6.4±1 μm deformation of NiMnGa particle is determined under the conditions of 6 specific points and the apparatus resolution of 1.67 μm. Then, the present evaluation method is concluded to be the useful and strong calculation way for the quantitative understanding of resolution-level local-micro deformation, especially based on in-house micro-focused X-ray computed tomography.

A schematic figure showing the occurrence of measurement error caused by apparatus resolution: (a) real shape, (b) image obtained by apparatus and (c) smoothed image where white circle is true specific point position and black circle is the measured point obtained in image.