Mech 2272

Introduction: Background Information and Theory

The main idea behind this experiment was to illustrate the significance of the main microscopic techniques that are used today in investigating the microscopic features of different metals and alloys. The main techniques demonstrated were: a) Metallographic sample preparation. b) Optical Microscopy. c) Scanning Electron Microscopy (SEM). Metallography is the study of the physical structure and components of metals, typically using microscopy. The surface of a metallographic specimen is prepared by various methods of grinding, polishing, and etching. After preparation, it is often analyzed using optical or electron microscopy. Using only metallographic techniques, a skilled technician can identify alloys and predict material properties. Metallographic sample preparation is beneficial in determining the microstructural features of different metals and alloys. The optical microscope, often referred to as the "light microscope", is a type of microscope which uses visible light and a system of lenses to magnify images of small samples. Optical microscopes are the oldest design of microscope and were possibly designed in their present compound form in the 17th century. Basic optical microscopes can be very simple, although there are many complex designs which aim to improve resolution and sample contrast. Optical microscopy is used extensively in microelectronics, nanophysics, biotechnology, pharmaceutic research, mineralogy and microbiology.

Optical Microscope

A scanning electron microscope (SEM) is a type of electron microscope that produces images of a sample by scanning it with a focused beam of electrons. The electrons interact with electrons in the sample, producing various signals that can be detected and that contain information about the sample's surface topography and composition. The electron beam is generally scanned in a raster scan pattern, and the beam's position is combined with the detected signal to...