INFLUENCE OF STRESS ON THE ELASTIC PROPER TIES OF THE GYPSUM SURFACE OBSERVED BY ATOMIC-FORCE MICROSCOPY

This paper introduces a new approach to studying the effects of latera l stress on surface elasticity Recent results in the force modulation with an atomic force microscope (AFM) on the (010) gypsum face are pre sented and discussed. At the atomic level, the images in the contact m ode differ from those mapping the elasticity. At the microscopic level , the images of elasticity vary according to the stress applied to the sample. Without stress, the surface stiffness is uniform. However, a lateral str ess induces slipping and shearing processes.