The hardening and loss of strength of thin surface layers of LiF monocrystals and zirconium ceramics under conditions of cyclic nanoindenting

Low-cycle surface fatigue is still relatively poorly investigated, especial ly in the case of accumulation of surface fractures during nanocontact inte ractions between solids. A new technique of modeling fatigue during a short nanocontact interaction based on repeated dynamic nanoindenting is propose d. The results of investigation of model LiF crystals and industrial ZrO2 c eramics show that, at a small number of cycles N of about 20, the material is hardened under the indenter. As N increases, the hardening is replaced b y a loss of strength reflected in the formation and growth of microcracks. (C) 2001 MAIK "Nauka/Interperiodica".