Elastic Recovery of Conical Indentations

This paper discusses the changes in shape which occur when a hard conical indenter is pressed into a metal (to form a plastic indentation) and then withdrawn. It is shown that there is little change in the diameter of the indentation during withdrawal but a decrease in its depth. This may be expressed analytically in terms of the elastic constants of the metal and there is reasonable agreement between the theoretical and observed changes in depth. The elastic energy released when the indenter is withdrawn may be calculated and it is shown that this accounts quantitatively for the elastic rebound observed when a conical indenter strikes an elasto-plastic metal. The analysis is also applied to the experimental results given by Davis and Hunter in 1959.