Simple test equipment has been developed for studying the elastic limit and plastic deformation of thin metal wires and thin foils (down to 10 μm) under torsion, tension, and bending. Using load-unload methods and gauge lengths up to 1 m, plastic strain as low as 10(-6) can be measured accurately.
Dunstan, D. J., Gallé, J. U., Ehrler, B., Schmitt, N. J., Zhu, T. T., Hou, X. D., ... Bushby, A. J. (2011). Micromechanical testing with microstrain resolution. Review of Scientific Instruments, 82(9). https://doi.org/10.1063/1.3636074