Mechanical property characterisation of small volumes of brittle materials with spherical tipped indenters

Spherical tipped indenters provide an attractive alternate approach for the characterisation of the mechanical properties of materials. Using this approach the elastic and plastic behaviour of a material may be investigated as well as the onset of ductility or yield. With the aid of a precision micromechanical probe or nanoindentation apparatus and very small indenters with radii of a few microns this approach enables one to also determine the stress–strain properties of very small volumes of materials. In this paper the basis of such an approach is outlined along with examples to illustrate the influence of ion-implantation on the mechanical properties of very thin layers of semiconductors, ceramics and other brittle materials. It is shown that such an approach enables a more critical appraisal of the behaviour of such materials than is possible with pointed indenters that generate constant strain contact response.