In-plane strain measurements on a microscopic scale by coupling digital image correlation and an in situ SEM technique

The purpose of this paper is to present a method based on the correlation of digital images obtained on a microscopic scale. A specific grainy pattern has been developed. The use of the scanning electron microscopy (SEM) allowed the determination of full-field 2D displacements on an object surface with a spatial resolution of about 1 μm. Validation tests were performed in order to quantify performances and limits of this method. An example of its application is presented for a Ti–6Al–4V titanium alloy. Results show that it is possible to obtain in-plane displacement values on the object surface with efficient spatial resolution and accuracy. Thus, such a technique can be used to highlight on a relevant scale the role of the microstructure in material deformation processes.