Legieren

Legieren is a metallurgical process in which two or more elements, typically metals, are combined to form a material with properties different from its constituent elements. The resulting material is called a Legierung (alloy). Alloying is driven by the desire to improve attributes such as strength, hardness, wear resistance, ductility, thermal stability, or corrosion resistance, often at the expense of other properties. The practice dates to antiquity, with bronze (copper and tin) representing one of the earliest known Legierungen.

In modern practice, alloying occurs mainly through melting and mixing of elements, followed by solidification. This fusion-based approach can be complemented by solid-state diffusion techniques or powder metallurgy, where elemental or pre-alloyed powders are blended and consolidated. After formation, heat treatment can homogenize the material and, in some cases, promote precipitation strengthening or phase transformations.

Common alloying systems include iron-based alloys (steel and stainless steel) with elements such as carbon, chromium, nickel, vanadium and molybdenum; copper-based alloys such as brass (copper and zinc) and bronze (copper and tin); aluminum alloys with magnesium and silicon; and titanium alloys with aluminum and vanadium. Each system offers a unique balance of properties suitable for specific applications.

Key considerations in legieren are compatibility of elements, solubility, phase structure, manufacturability, and cost. Some alloys improve performance at higher temperatures or in corrosive environments, while others optimize machinability or weight. The design of an alloy often involves trade-offs between strength, ductility, hardness, and toughness, as well as service conditions and production methods.