Examinando por Materia "Microdureza"

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    Ítem
    Microestructura y propiedades mecánicas de las fases fundamentales del Clinker
    (Universidad EAFIT, 2021) Castro Puerta, Camila Andrea; Ossa Henao, Edgar Alexander
    Due to the high importance of the cement between the construction material, in the present work the micromechanical properties of the main clinker phases was determined. There was an initial investigation of the history and fabrication of the Clinker, the function of each of its phases, and its hydration process, concluding that the alite and the belite are the phases that provides the mechanical resistance to the hydrated cement therefore the phases to which their resistance was analyzed. For a reference the hardness of previous research works was sought for both phases. For the experimental part the samples of clinker rock were prepared, were embedded in epoxy and polished carefully, different attack chemicals were searched for the phase differentiation, once the identification was achieved, the Vickers hardness test was performed with a micro-hardness tester, with a pyramid-shaped diamond indenter with a square base, it is explained how to obtain the ideal load at which this material should be indented. Once the indentations were completed, a data analysis was performed by means of a onefactor analysis of variance, where the hardness values obtained were concluded to be valid, which additionally are in accordance with those found in the literature and are the following: HvAlita=9.26GPa y HvBelita=7.03GPa. In addition to the hardness, apparent fracture toughness was analyzed, for which very scattered data were obtained, especially in belite where fractures did not occur in the corners.
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    Study Experimental and Numerical Simulations of the Micro-hardness Tests in AL-FE alloy in Different Laser Beam Scanning
    (Universidad EAFIT, 2019-11-29) Meza Pariona, Moises; Universidade Estadual de Ponta Grossa
    In the Al–2.0 wt.%Fe alloy the laser surface remelting (LSR) treatment was executed to investigate the treated and untreated layers areas, at different laser beam scanning, among them, 80, 100 and 120 mm/s, to respect, was presented and discussed about microstructural characteristics using the FEG and EDS techniques, and numerical experiments of pyramidal indentations of the LSR-treated systems were conducted using the FEM method. In the sample-treated cross-sectional area, the microstructure presented a columnar growth characteristic, a lot of nano-porosities and large size of the molten pool geometry in low laser beam scanning, however, in high laser beam scanning, the microstructure consisted of a cellular arrangement or fine-grained microstructure, the nano-porosities concentration and the molten pool geometry are slightly decreased. Besides, the micro-hardness in the LSR-treated area increased slightly as a function of increase of the laser beam scanning, but, the micro-hardness was much higher than the untreated sample. Meanwhile, modeling of indentation on COMSOL of the LSR-treatment by finite element method of the micro-hardness was successfully calculated. Therefore, a good agreement was found between experimental and simulated data.