Metallography

Metallography is the study of crystal structures and phase components of metals. The properties of metals are controlled by both their microstructures and chemical compositions. For example, different microstructures could occur depending on heat treatment or solidification process for a steel specimen with the same chemical compositions. With proper cutting, polishing and etching process, the microstructure of a metal could be revealed usually with optical microscopy. By revealing material microstructures, both naturally occurring and resulting from engineering processes, metallography studies could identify metallurgical characteristics of materials such as phases, grain sizes, crystal orientations, defects and voids, phase separations, cracks and inclusions. Metallography is also one of the primary tools to analyse metal failure mechanisms including fatigue, corrosion, creep, stress ruptures, fractures, cracking and hydrogen embrittlement.

Typical Experimental Results

Optical metallograph of a malleable cast iron showing spheroidal graphite in a ferrite matrix

Optical micrograph showing dark pearlite patches distributed in the matrix of ferrite grains of a low-carbon steel surface

Applications

Instrument: Zeiss Axiotron Inspection Microscope

Instrument Key Specifications

Hysitron TriboIndenter Optics

CSM Scratch Tester Camera System

AmScope Stereo Tri-ocular Microscope

For more information, please read our application notes:
Mineral Identification in Geological Samples, PDF
Low-Cycle Fatigue Failure of a Steel Wire, PDF
Impact Fracture of a Metallic Hood Ornament, PDF
All application notes can be found here