Indentation of power law creep solids by self-similar indenters

For creep solids obeying the power law under tension proposed by Tabor, namelyσ=bε˙m,it has been established through dimensional analysis that for self-similar indenters the load F versus indentation depth h can be expressed asF(t)=bh2(t)h˙(t)h(t)mΠαwhere the dimensionless factor Πα depends on material parameters such as m and the indenter geometry. In this article, we show that by generalizing the Tabor power law to the general three dimensional case on the basis of isotropy, this factor can be calculated so that indentation test can be used to determine the material parameters b and m appearing in the original power law. Hence indentation test can replace tension test. This could be a distinct advantage for materials that come in the form of thin films, coatings or otherwise available only in small amounts. To facilitate application values of this constant are given in tabulated form for a range of material parameters.