Materials Science

The ordered, repeating three-dimensional arrangement of atoms, ions, or molecules in a crystalline solid. Common crystal structures include face-centered cubic (FCC), body-centered cubic (BCC), and hexagonal close-packed (HCP), each conferring different mechanical and physical properties.

A graphical representation showing the stable phases of a material system as a function of temperature, pressure, and composition. Phase diagrams are essential tools for predicting material behavior during processing and service.

Linear defects in the crystal lattice where atoms are misaligned. Dislocations are the primary mechanism by which metals deform plastically. Their movement, multiplication, and interaction govern a material's strength and ductility.

The molecular structure of polymers, including chain length, branching, cross-linking, and the arrangement of repeat units. These structural features determine whether a polymer is a flexible thermoplastic, a rigid thermoset, or an elastic elastomer.

Engineered materials made from two or more constituent materials with significantly different properties that, when combined, produce a material with characteristics superior to either component alone. The constituents remain distinct at the macroscopic level.

The thermally activated process by which atoms or molecules migrate through a material. Diffusion governs many critical phenomena including phase transformations, oxidation, sintering, doping of semiconductors, and creep deformation at elevated temperatures.

The study of how cracks initiate, propagate, and lead to failure in materials. It provides the theoretical framework for predicting the conditions under which a material will fail, using concepts such as stress intensity factor and fracture toughness.

Materials with electrical conductivity between that of conductors and insulators, whose properties can be precisely controlled by introducing small amounts of impurity atoms (dopants). Silicon and germanium are elemental semiconductors; gallium arsenide is a compound semiconductor.

Materials with at least one dimension in the nanometer range (1-100 nm). At this scale, materials exhibit unique properties due to quantum effects and their extremely high surface-area-to-volume ratio, differing significantly from their bulk counterparts.

The electrochemical degradation of materials, particularly metals, through reaction with their environment. Corrosion involves the oxidation of a metal at an anodic site and a corresponding reduction reaction at a cathodic site, often in the presence of moisture and electrolytes.