Topic
Indentation
About: Indentation is a research topic. Over the lifetime, 13002 publications have been published within this topic receiving 340476 citations.
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TL;DR: In this paper, the effect of various tool rotatations on friction stir processing of Al6061-SiC-Graphite hybrid composites is studied in detail via force analysis, spectroscopic, microstructural and indentation studies.
Abstract: Friction stir processing (FSP) of Al6061-SiC-Graphite hybrid composites is studied in detail via force analysis, spectroscopic, microstructural and indentation studies. Effect of various tool rotat...
89 citations
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01 Jan 1983
89 citations
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TL;DR: In this article, it was shown that the difference in indentation microhardness is due to differential effects of water adsorption on the opposite polar faces rather than being an intrinsic polar mechanical property of the crystal, and the usefulness of such measurements for absolute determinations of crystallographic polarity of non-centrosymmetric crystals is discussed.
Abstract: Marked changes in indentation microhardness have been observed in a wide range of non-metallic materials due to the presence of adsorbed water and other polar species. Opposite polar faces of crystals with non-centrosymmetric structures, including II–VI, III–V and IV–IV compounds, exhibit large differences in microhardness and anomalous indentation creep behaviour. Such differences are shown to be due to differential effects of water adsorption on the opposite polar faces rather than being an intrinsic polar mechanical property of the crystal. The usefulness of microhardness measurements for absolute determinations of crystallographic polarity of non-centrosymmetric crystals is discussed. Effects of environment on the extent of edge dislocation motion away from the indentation are examined. Possible mechanisms to explain the adsorption-induced changes in microhardness and related mechanical properties of non-metallic solids are critically discussed.
89 citations
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TL;DR: In this paper, a simple and easy indentation hardness test is proposed to predict the uniaxial compressive strength (UCS) and Brazilian tensile strength (BTS) of rock for designing surface and underground structures.
Abstract: Rock engineers have commonly used the uniaxial compressive strength (UCS) and Brazilian tensile strength (BTS) of rock for designing surface and underground structures. Determining these rock strengths is timeconsuming and expensive, particularly for the preliminary studies of projects. For this reason, indirect tests such as Schmidt rebound number and, ultrasonic test are often used for predicting rock strength. Since indirect tests require less or no sample preparation and the testing equipment is less sophisticated, these tests are very easy to carry out. In addition, these tests can usually be performed in the field. The indentation hardness test is a simple and easy test and can be conducted using a point load test apparatus. The test is of particular value when only a limited amount of rock material, e.g. a thin disc of core or a small lump sample, is available1. The UCS and BTS can easily be predicted from the indentation hardness index (IHI) for the preliminary investigations, if strong predictive correlations are established. Since rock indentation is the basic process in drilling and boring, numerous researchers2–16 have carried out indentation tests to understand the indentation phenomena or to develop prediction models for drilling or boring. Kahraman et al.15 also investigated the relationships between the slope of load-indentation curves and the rock properties. They found good correlations between the slope of load-indentation curves and the rock properties. Kahraman and Gunaydin17 investigated the sawability prediction of carbonate rocks from indentation hardness tests carried out by attaching a dial gauge to the point load apparatus for measuring penetration. They concluded that the indentation hardness test can be used for predicting the sawability of carbonate rocks. Recently, Yagiz18 suggested a new brittleness index and rock brittleness classification based on type, strength, and density of rock together with the results of punch penetration tests. A standard indentation test was recommended by ISRM1 and Equation [1] was suggested for the prediction of UCS from IHI
89 citations
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IBM1
TL;DR: In this paper, the authors measured the propagation of indentation radial cracks in soda-lime silicate glass and showed distinct threshold, reaction-limited and transport-limited behavior in the crack velocity responses, in agreement with measurements made using macroscopic crack geometries.
Abstract: The propagation of indentation radial cracks in soda—lime silicate glass is measured as a function of time after indentation. Rapid lift-off of the indenter from the specimen surface causes a step-function perturbation in the radial crack mechanical energy release rate, thus providing access to a large range of observable crack velocities in the indentation stress field. Analysis of the data shows distinct threshold, reaction-limited, and transport-limited behavior in the crack velocity responses, in agreement with measurements made using macroscopic crack geometries. Atomistic models of fracture kinetics in reactive environments are fit to the data and are deconvoluted to yield the underlying atomic-scale, bond-rupture parameters. These latter are used to calculate potential functions for activated fracture and predict crack velocity responses as a function of temperature and pressure.
89 citations