MICROSCOPIC EXAMINATION OF METALSIn this experiment, our goal is to examine the microstructure of metals. By studying the microscopic structures of metals, we determine which material is best suited to a particular application. We used the most common method, the optical technique, to examine the microstructure. We used a small sample cut from the metal to be examined. In order to be able to see the structure clearly, we first cleaned and polished the sample. First we start polishing with emery paper no. 1 and some finer gradations. Care should be taken with coarse abrasive particles and streaks from them. Cleaning and rotating the sample 90° during transfer can prevent them. The next step is polishing, but washing the sample before polishing gives a better result. Finally, we polished the sample on a rotating cloth coated with an effective abrasive such as Al2O3-Water suspension. We continued polishing until we got a mirror face. After finishing the polishing, it was possible to reveal the crystalline structure of the sample, any cracks, seams, non-metallic inclusions and inhomogeneities. Before starting the engraving, we applied the mounting process. In this step we used a matching die set. We positioned our sample in the matrix so that the rough face of the sample was the bottom surface and the shiny face faced up. We filled the mold cavity with Bakelite and then transferred our mold into a press. Mounting not only protects our sample, but also making its base flat and stable helps us while examining the sample under the microscope. In the etching process, depending on the chemical composition, energy content and grain orientation, we determine grain boundaries and the presence of chemically different phases. To reveal these microstructural details of the polished frame we used an etchant such as 1% Nital.