Methods and devices are disclosed for tracking site-specific microstructure evolutions and local mechanical fields in metallic samples deformed along biaxial strain paths. The method is based on interrupted bulge tests carried out with a custom sample holder adapted for SEM-based analytical measurements. Embodiments include elliptical dies used to generate proportional and complex strain paths in material samples. One example holding device includes a base having a floor and walls that extend to form a chamber for a sample, the floor having apertures for receiving a pressure-supplying fluid, a cover having an opening and configured such that the cover and base can be coupled together to tightly clamp a sample in the chamber, and washers disposed between the base and the cover, each washer having openings extending therethrough change at least one of a shape and a size of the opening formed in the cover.