CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS

**Definition:** This place covers:

Changing the physical (metallurgical) structure of non-ferrous metals or alloys by heat treatment or by hot or cold working;

Changing the physical structure of non-ferrous metals or alloys by special physical methods, e.g. treatment with neutrons.

The term "non-ferrous alloys" refers to alloys based essentially on metals other than iron.

**Limiting references (this place does not cover):** - Working metallic powder, powder metallurgical apparatus or processes -> B22F , C22C1/04 - Heat treatment, e.g. annealing, quenching, tempering, adapted for particular metallic articles; furnaces therefor -> C21D9/00 - Electrolytic production or refining of metals -> C25C - Single crystals or homogeneous polycrystalline material with defined structure; production thereof -> C30B

**Glossary:** - Alloy: A composition of plural elements at least one of which is a free metal. It also includes material containing any combination of fibres, filaments, whiskers and particles, e.g. carbides, diamond, oxides, borides, nitrides, silicides, or other metal compounds, e.g. oxynitrides or sulfides embedded in a metallic matrix - Recrystallization: After all metal crystals have been dissolved by heating enough to lose its structural strength, the metal temperature then falls, allowing the crystals to re-form - Aging (or ageing): A process in which the hardness or strength of a metal alloy having a constituent in supersaturated solid solution is increased over time as the constituent precipitates out as a secondary phase containing the constituent. When occurring at room temperature the process is termed "natural aging", while a process that occurs when subjecting the metal alloy to elevated temperature is termed "artificial aging". Aging for a longer time than that corresponding to maximum strength or hardness at the particular temperature is termed "over-ageing". - Hardening: The increase in resistance to deformation - Precipitation hardening: As the quenched alloy ages, a new material precipitates out of the metallic crystal lattice, filling in abutting spaces, and increasing hardness - Normalizing: A process of heating metallic material above its critical temperature and cooling in air thereby establishing a fine uniform grain size and improving the microstructural uniformity - Quenching: The rapid cooling of metallic material either from elevated temperature to room temperature or cooling of metal to sub-ambient temperature, at a specific rate, with a given medium. - Tempering: Heating of a previously quenched or normalized metallic material to an elevated temperature, and then cooling under suitable conditions to obtain the desired mechanical properties.