Depth-sensing indentation testing

Depth-sensing Indentation Deformation Wear Tests and Their Effects on... 

FIGURE 33.1 Schematic of a depth-sensing indentation (DSI) test. An indenter is pushed with force, F, into the surface an amount, h. The load-depth curve is generated. A schematic for a spherical indenter is shown. Corrections for the contact area calculation are made by finding he = (hmax+hr)/2. The parameters, hj. Fmax HE, and dF/dh are used to find the hardness, modulus, and energy dissipation resulting from indentation. 

One of the primary distinctions between depth sensing indentation and conventional microhardness testing is the manner in which the contact area is established from an analysis of the load-displacement data rather than by imaging of the indentation after the load is removed and measuring the diagonal lengths [11]. 

The measurement of local mechanical properties is an important step in understanding of the macroscopic behavior of multiphase materials. The indentation hardness test is probably the simplest method of measuring the mechanical properties of materials. Figure 12.2b shows the evolution of the microhardness as a function of the thermal treatment temperature of a Nasicon sample. The use of load-controlled depth-sensing hardness testers which operate in the (sub)micron range enables the study of each component of the composite more precisely. 

Mechanical and Chemical Characterization Enamel has often been viewed as a homogeneous solid [2, 3], but Knoop microhardness tests [4, 5] and compression tests [6] have shown that the Young s modulus (E) and hardness (H) are higher for cusp (or surface) enamel than for side (or subsurface) enamel. Depth-sensing Vickers indentation [7] has shown that the H and E obtained from an occlusal section of enamel are higher than those for an axial section. The variations in mechanical properties with location have been explained in terms of the degree of tissue mineralization. Notably,... 

Nanoscratch tests have been used to simulate the effect of third-body particulate wear debris on component surface scratching during use. The load at which the co-efficient of friction or friction force suddenly increases is identified as the critical load, and is used to evaluate scratch resistance and adhesion strength. The depth-sensing nanoindenter, usually equipped with a conical indenter, can elucidate the mode of failure, whether elastic/plastic deformation, cracking, or delamination. 

As additional information, the curve of the indentation size eflFect of sapphire in Fig. 8 was complemented by data measured and analyzed by Oliver and Pharr [19] on a (0001) plane. It is very remarkable that neither the different crystals and orientations, nor the different (depth sensing) measurements (Vickers-Berkovich) and the very different data analyses affect the character of the size effect observed in sapphire it can be described by one curve according to Eq. (3)/(3a) for available data in an extremely wide range of testing loads between 1 mN and 100 N. 

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