Microstructure is the very small scale structure of a material, defined as the structure of a prepared surface of material as revealed by an optical microscope above 25× magnification. The microstructure of a material can strongly influence physical properties such as strength, toughness, ductility, hardness, corrosion resistance, high/low temperature behaviour or wear resistance. These properties in turn govern the application of these materials in industrial practice.
A micrograph of bronze revealing a cast dendritic structure
Microstructure of a spiral tube originating from the 12th-13th century cemetery from Kukruse, Estonia. Copper alloy wire containing tin and lead. The spiral was mounted in plastic and ground. Tint etched with the Klemm's II reagent. Photographed with optical microscope under 200x magnification.
A computer simulated microstructure of composite materials
A polymer
is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic and natural polymers play essential and ubiquitous roles in everyday life. Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as DNA and proteins that are fundamental to biological structure and function. Polymers, both natural and synthetic, are created via polymerization of many small molecules, known as monomers. Their consequently large molecular mass, relative to small molecule compounds, produces unique physical properties including toughness, high elasticity, viscoelasticity, and a tendency to form amorphous and semicrystalline structures rather than crystals.
Appearance of real linear polymer chains as recorded using an atomic force microscope on a surface, under liquid medium. Chain contour length for this polymer is ~204 nm; thickness is ~0.4 nm.
A polyethylene sample that has necked under tension
A plastic item with thirty years of exposure to heat and cold, brake fluid, and sunlight. Notice the discoloration and crazing of the material (compared with replacement item in foreground).
Chlorine attack of acetal resin plumbing joint