Investigation of ultra low indentation loading at elevated temperatures based on the hydrostatic stress-induced mass flow model

A mechanism of hydrostatic stress-induced mass flow is proposed to describe a medium under an action of ultra low load indentation at elevated temperatures. Two types of indenters of conical and spherical shapes and two loading conditions of constant indentation speed and constant load were used in the investigation. For both shapes of indenters, the maximum hydrostatic stress is located in the vicinity of the indentation tip. The maximum hydrostatic stress is proportional to the indentation speed and applied load, but inversely proportional to the atomic mobility. Comparing the loading conditions, the maximum hydrostatic stress is linearly proportional to the indentation area at constant indentation speed, but inversely proportional to the indentation area at constant applied load.