intermetalické

Intermetalické, or intermetallic compounds, are crystalline materials formed by two or more metallic elements in fixed, definite ratios and with ordered crystal structures. Unlike many conventional metallic alloys that form solid solutions, intermetallics exhibit specific stoichiometries and lattice types that repeat throughout the material, producing properties that differ from the constituent metals.

These compounds form through diffusion and ordering processes when elements are combined at suitable temperatures. Common stoichiometries include AB, A2B, AB2, and A3B, with crystal structures ranging from simple lattices to complex ordered types. Notable structure types include B2 (CsCl-type, as in NiAl), L12 (gamma prime, Ni3Al), L10 (gamma-TiAl), and various Laves phases (C14, C15, C36).

Intermetallics typically display high melting points, high stiffness, and good oxidation or corrosion resistance, especially at elevated temperatures. However, they often behave brittlely at room temperature due to their highly ordered bonding, leading to limited ductility and fracture toughness. Properties are often anisotropic and highly sensitive to composition and processing history.

Industrial relevance centers on aluminides and other intermetallics designed for high-temperature applications. Examples include NiAl and Ni3Al for oxidation-resistant coatings and high-temperature components, TiAl-based alloys for lightweight turbine blades, and FeAl and Fe3Al for corrosion-resistant structural materials. Processing methods include casting, powder metallurgy, and diffusion-based treatments to optimize ordering and reduce defects.

Intermetallics remain an active area of materials science because of their attractive high-temperature properties and the ongoing challenge of improving ductility and toughness without sacrificing performance.