Patent ID: 7149634

Claim:
A method of understanding the mechanical properties of a material comprising: determining the elastic modulus of a material having a Poisson's ratio v by a Berkovich indenter having an elastic modulus E i , a Poisson's ratio v i , and a cross sectional area A(h) as a function of depth h, including the following steps a) to h): a) modeling the Berkovich indenter with a conical shape with a spherical cap providing a blunt tip which is assigned to have a half-included θ, and a radius R of the cap or an absolute bluntness value Δh to ensure that its cross sectional area is the same as that of the real indenter for all h values; b) measuring maximum load P m , maximum indentation depth h m , elastic work W e and total work W; c) calculating nominal hardness H n , where; H n = P m A ⁡ ( h m ) ; d) calculating a set of estimates of H n E r from a set of relationships between H n E r ⁢ ⁢ and ⁢ ⁢ W e W derived from numerical simulations of indention processes corresponding to different settings of relative bluntness defined as Δh/h m , wherein; 1 E r = 1 - v 2 E + 1 - v i 2 E i ; e) determining H n E r corresponding to the experimentally measured Δh/h m value through interpolation; f) calculating a reduced elastic modulus E r of the material by dividing H n with the estimate H n E r value; g) calculating the material elastic modulus E from; E = 1 - v 2 1 E r - 1 - v i 2 E i . h) utilizing the calculated elastic modulus E to understand the mechanical properties of a material.