SPHERICAL NANOINDENTATION AND KINKING NON-LINEAR ELASTICITY IN GEOLOGY

The physical mechanism responsible for nonlinear elastic, hysteretic, and discrete memory response of nonlinear mesoscopic elastic (NME) solids has only been identified recently.[1] Herein we show, by nanoindenting layered minerals like muscovite, biotite, brucite among others that this response is most likely due to the formation of dissipative and fully reversible, dislocation-based kink bands. We further claim that solids with high c/a ratios, which per force are plastically anisotropic, will deform by kinking. These kinking nonlinear elastic solids include layered ternary carbides, nitrides, oxides, and semiconductors, ice, graphite, and the layered phases, such as mica, present in nonlinear mesoscopic elastic solids. This work also demonstrates the availability of a relatively simple non-destructive technique, which requires tiny samples to probe such solids at geologically relevant stresses, is a huge advantage that should lead to rapid advancement in our understanding and one that should prove of immense benefit.

Ref. 1: M.W. Barsoum, A. Murugaiah, S.R. Kalidindi, T. Zhen, Kinking Nonlinear Elastic Solids, Nanoindentations and Geology, Phys. Rev. Lett. 92 (2004) 255508-1.