This is performed on samples either cut to size or mounted in a resin mold. The samples are polished to a fine finish, normally one micron diamond paste, and usually etched in an appropriate chemical solution prior to examination on a metallurgical microscope.
Micro-examination is performed for a number of purposes, the most obvious of which is to assess the structure of the material.
It is also common to examine for metallurgical anomalies such as third phase precipitates, excessive grain growth, etc. Many routine tests such as phase counting or grain size determinations are performed in conjunction with micro-examinations.