Microscopic material characterization using SEM topography images correlation

A novel microscopic strain mapping technique has been developed based on the analysis of surface topography using digital image correlation (DIC) software (J. Kang et al, Journal of strain analysis for engineering design, 40(6), 559-570, 2005). The input is a series of scanning electron microscopy (SEM) images. The method uses topographic features found in these images as the input. A commercially available optical strain measurement system (ARAMIS®) which utilizes the DIC methodology is used for this purpose. In this paper, the method has been further validated in various applications such as using slip traces in tension aluminum alloy and fatigue of magnesium alloy, as well as microstructure features in tension of steel sheet. The selection and processing of the SEM images to achieve the best possible accuracy of the strain mapping results are discussed in detail.