Cyclic microindentations on monocrystalline silicon in air and in water

Abstract

This paper studies the difference in the mechanical response of monocrystalline silicon to cyclic microindentations in air and in water. It shows that in air the indentations with a spherical indenter generated consequent phase transformations. In the first indentation cycle, the decomposition featured amorphous phase at low maximum indentation load, Pmax, that was converged to a crystalline compound in repeated indentations. A high Pmax generated crystalline R8/BC8 phases only. After a few cycles, the transformed material behaved linearly elastically, and its properties became stable. However, when the same indentations were conducted in water, the property stabilization process of the transformed material was significantly slowed down, featuring non-linear elasticity. It seemed that at a high Pmax a chemical effect took place in the central part of the transformation zone.