Metallographic analysis is a technique used to examine the microstructure of a metal, which includes identifying the different phases present in the metal.

Sample preparation is the process of preparing a metallographic specimen for analysis. It involves cutting, mounting, grinding, polishing, and etching the specimen to reveal its microstructure.

An etchant is a chemical solution used to selectively attack and dissolve certain phases in a metallographic specimen, revealing the grain boundaries and other microstructural features.

Optical microscopy is a widely used technique for metallographic analysis. It involves using a light microscope to examine the microstructure of a metallographic specimen.

A phase diagram is a graphical representation of the phases that exist in a metal alloy system as a function of temperature and composition. It is used to predict the phases present in a metal at a given temperature and composition.

A single-phase alloy has a uniform microstructure, meaning that it consists of only one type of crystal structure. A multi-phase alloy, on the other hand, has a heterogeneous microstructure, meaning that it consists of two or more different crystal structures.

Grain boundaries provide a path for the movement of dislocations, which are defects in the crystal structure of a metal. This allows dislocations to move more easily through the metal, making it more ductile.

Heat treatment can change the phase composition, refine the grain size, and alter the mechanical properties of a metal.

Quenching is a common method for hardening a steel alloy. It involves rapidly cooling the steel from a high temperature to room temperature, which traps carbon atoms in the crystal structure of the steel, making it harder.

Tempering is a process that is performed after quenching to reduce the hardness of the steel, increase its toughness, and improve its machinability.

Pitting corrosion, crevice corrosion, galvanic corrosion, and stress corrosion cracking are all common types of corrosion.

Pitting corrosion is caused by the localized breakdown of the protective oxide layer on the metal surface, leading to the formation of pits or cavities in the metal.

Applying a protective coating to the metal surface, using sacrificial anodes, and cathodic protection are all common methods for preventing corrosion.

A sacrificial anode is a more active metal that is connected to the metal being protected. It corrodes instead of the metal being protected, thereby protecting it from corrosion.

Cathodic protection involves applying a negative potential to the metal being protected, which prevents the metal from corroding.