Micro-Indentations

B. W. Mott, Micro-indentation Hardness Testing, p. 247, Butterworths Scientific Publications, London, UK (1956). 

L. Olivier, N. Q. Ho, J. C. Grandidier, and M. C. Lafarie-Frenot, Characterization by Ultra-Micro Indentation of an Oxidized Epoxy Polymer, Pol. Degrad. Stab., 93,... 

Kharrat, M., Chateauminois, A., Carpentier, L. and Kapsa, P., On the interfacial behavior of a glass/epoxy composite during a micro-indentation test assessment of interfacial shear strength using reduced indentation curves, Composites, A, 28, 39 (1997). 

Netravali, A.N., Stone, D., Ruoff, S. and Topoleski, L.T.T. (1989b). Continuous micro-indenter push-through technique for measuring interfacial shear strength of fiber composites. Composites Sci. Technol. 34, 289-303. 

Meda, G., Hoysan, S.F. and Sleif, P.S. (1993). The effect of fiber Poisson expansion in micro-indentation tests. Trans. ASME J. Appl. Mech. 60, 986-991. 

Although Vickers and DPH microhardness tests should yield the same numerical results on a given material, such is not always the case. Much of the observed variance maybe a function of differences in the volume of sample material displaced by the macro and micro indentations. 

Bowie S. H. U., 1967, Micro-indentation hardness, in J. Zussamann (Ed.), Physical Methods in Determinative Mineralogy, Academic Press, London. 

Mott B. W., 1960, Micro-Indentation Hardness Testing, Butterwords, London. 

Mahoney E, Holt A, Swain M, Kilpatrick N The hardness and modulus of elasticity of primary molar teeth an ultra-micro-indentation study. J Dent 2000 28 589-594. 

Vicker s hardness number (VHN). Hardness on Rockwell and Brinell scales are also reported for metals and alloys. In both KHN and VHN measurements, the approach is to make an indentation on the surface of the sample using a diamond micro-indenter. In the Vicker s method the indenter has the shape of a square pyramid, while in the Knoop s method it has the shape of an elongated pyramid. The indentation is generally of the order of few microns and a load of 5 to 1000 gm are used (in order to determine fracture toughness, it becomes necessary to use higher values of load (due to the necessity of initiating cracks)), VHN is given by. 

The composite, metal substrate, and braze foils (two layers, -100 pm total thickness) were sliced into 2.54 cm x 1.25 cm x 0.25 cm pieces and ultrasonically cleaned in acetone for 15 min. The braze foil was sandwiched between metal and composite, and a normal pressure of 1.2-4.7 kPa (0.38-1.5 N) was applied to the assembly. The assembly was heated in a furnace to -15-20 °C above the braze liquidus under vacuum (10 torr), soaked for 5 min., and slowly cooled to room temperature. The brazed joints were prepared for metallography and examined with a Scanning Electron Microscope (SEM) coupled with energy dispersive x-ray spectroscope (EDS) on a JEOL-840 A unit. Microhardness scans were made with a Knoop micro-indenter on a Struers Duramin A-300 machine under a load of 200 g and loading time of 10 s. 

In general, the available indentation techniques are based either on scanning force microscopy (SFM) or on dedicated indentation setups providing well-defined tip geometries. The two approaches are described in Sections 8.2.1 and 8.2.2, respectively. Issues related to potential artifacts in IP characterization are discussed in Section 8.3. Finally, examples of epoxy IP characterization by means of SFM-based stiffness mapping as well as depth-sensing micro-indentation (DSI) are given in Sections 8.4.1 and 8.4.2, respectively. 

Fig. 8.8 (a) Topography image of a field of micro-indentations across the left-hand epoxy IP. The interface is marked with a black solid line, on the right of which is located PVP. The experiments were performed using the setup described in Section 8.2.2. 

L. Angkur, N. Nijhof, M.V. Swain, N.M. Kilpatrick, Influence of hydration and mechanical characterization of carious primary dentine using an ultra-micro indentation system (UMIS), Eur. J. Oral Sci. 112 (2004) 231-236. 

Anand, L. and Ames, N.M. (2006) On modeling the micro-indentation response of amorphous polymer. 

Field emission research and applications Diamond coated scanning tunneling microscopy Micro-indentation and micro-tools Dense whisker arrays as high absorption light traps Dense whisker arrays as high emissivity light sources Microsubstrates and array substrates ... 

Micro indentation data reveals hardness profile of LDPE/EPDM blends, staying in agreement with structural data for the surface layer of systems studied. 

Inclusions are sometimes observed buried in the surface of fibers, indicating a dirty fiber drawing environment as their most likely source. Impact by dust particles at low temperatures (below glass transition temperatures) causes only micro-indents and the... 

Sekimnra N, Kamada T, Wakasngi Y, Okita T and Arai Y (2002), Evalnation of radiation hardening in Fe alloys nnder heavy ion irradiation by micro-indentation technique , / Nucl Mater, 307-311,308-311. 

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