Instrumented Indentation to Characterize Mechanical Behavior of Materials

FRONTINI, PATRCIA MARÍA ; FASCE, LAURA ALEJANDRA

Campana

Congreso; VIII Congreso Regional de Ensayos No Destructivos y Estructurales CORENDE; 2011

Asociación Argentina de Ensayos No destructivos y Estructurales

The recent emergence and proliferation of the surface force apparatus and computational techniques for simulating tip-surface interactions have led to the appearance of a new form of mechanical characterization of materials tribology and contact mechanics: the so-called Depth Sensing Indentation. Indentation experiments and analysis are widely used in characterizing the mechanical properties of materials. It has two inherent advantages: it is a low destructive test, the specimen is neither fractured nor excessively deformed, and only a small amount of material is needed. Instrumented indentation was developed in the 70s [Frohlich et al., 1977]. This new machine continuously records the applied load and displacement of the indenter tip during a test, enabling the determination of mechanical properties for design purposes. These systems have been used to indent hard inorganic engineering materials (e.g, metals, ceramics, thin films, hard coatings, polymers, soft and biological materials and semiconductors). With this technique it is possible to determine elastic moduli [W.C. Oliver and G.M. Pharr, 1992; M.F. Doerner and W.D. Nix, 1986], time dependence of soft materials [B.N. Lucas and O. W.C., 1999], fracture toughness [J.S. Field et al., 2003], interfacial adhesion [Mondher Zidi Et al., 2001] and plasticity of metals [J.S. Field and M.V. Swain, 1995]. The most commonly used tip shapes are: the Berkovich (tip-three side pyramid), the sphere, the cone and the flat-ended punch tip. Besides, by using the inverse problem technique, which involves introducing known properties into a numerical model and recovering them by an appropriate algorithm [J. L. Bucaille et al., 2003; Y. P. Cao, 2004] it is possible to extract complex stress field mechanical constitutive equations [A.C. Fischer-Cripps, 2007; C. Yan Ping et al., 2007; S. Siqi et al., 2007; A.H.W. Ngan, 2005]. Through this work several examples involving different features of materials characterization via instrumented indentation are shown.