METHOD AND APPARATUS FOR DETERMINING MECHANICAL FEATURES OF A MATERIAL WITH COMPARISON TO REFERENCE DATABASE

WIPO Patent Application WO2006013450

A3

A method for detecting mechanical features of a material, in particular a metal material, provides a preliminary step where a database is created containing a finite number of reference curves (P,h) (52) . Such curves are obtained using a finite elements analysis and reproduce the trend of the applied force (P) responsive to the penetration depth (h) during an indentation test. The reference curves (P,h) are obtained for a determined number of different materials having a known elastic modulus E, and values of yield stress (s_sn)_{and strain­ hardening coefficient (n) comprised within determined ranges. The tested sample is then arranged at an indenter, for example a ball indenter (52), for being subject to an indentation test. This is started to cause a graduated penetration of the indenter in the material subject to analysis (53). During the indentation test the penetration depth (h) responsive to the penetration force (P) are measured, and a succession of measured couples (P,h) (54)is then recorded. Such couples of determined values (P,h) are then computed (55), in order to extrapolate from the database at least one reference curve (P,h), for example by a least squares method (56).}