Microscopic Boundary Examination :: essays research papers

MICROSCOPIC EXAMINATION OF METALSIn this experiment, our aim is examining the microstructure of metals. By perusal microscopic structures of metals, we determine which material fits best to a given application. We utilize the most common method, optical technique, to examine the microstructure.We used a microscopical ideal cut from the metal to be examined. To be able to implement the structure clearly, we first cleaned and polished the specimen. First we start polishing with emery root word no 1 and some finer grades. One should be thrifty about the coarse abrasive particles and striations from them. Cleaning and rotating the specimen 90 during the channelize can prevent these. The next step is polishing, yet washing the ideal before polishing gives a more successful result. Finally, we polished the specimen on a rotating cloth covered with an effective abrasive alike Al2O3-Water suspension. We kept polishing until we obtained a mirror like caseful.After we undefiled po lishing, the crystalline structure of the specimen, any cracks, seams, non-metallic inclusions and inhomogenities, could be revealed. Before start etch we first applied mounting process. In this step we used a matched die set. We placed our audition into the die set in the counselling that the rough face of the specimen was the lower surface and the polished face looked upward. We filled the die cavity with Bakelite and then we transferred our die to a mounpress. ascent not only protects our sample but also by devising its base flat and stable helps us while we are examining the sample under the microscope. In etching process, depending upon chemical composition, energy content and texture orientation, we determine the grain boundaries and the presence of chemically different phases. To reveal these micro structural details of the polished mount we used an etchant like 1% Nital.