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Precipitation hardening, also called age hardening or particle hardening, is a heat treatment technique used to increase the yield strength of malleable materials, including most structural alloys of aluminium, magnesium, nickel, titanium, and some steels, stainless steels, and duplex stainless steel.
A Guinier–Preston zone, or GP-zone, is a fine-scale metallurgical phenomenon, involving early stage precipitation. [1] [2] GP-zones are associated with the phenomenon of age hardening, whereby room-temperature reactions continue to occur within a material through time, resulting in changing physical properties. In particular, this occurs in ...
The hardening process requires rapid cooling of the annealed metal, resulting in a solid-state solution of beryllium in copper, which is then kept at 200-460 °C for at least an hour, producing a precipitation of metastable beryllide crystals in the copper matrix. Over-aging beyond the equilibrium phase depletes the beryllide crystals and ...
An example of the use of the nickel-based superalloys in the industrial field would be turbine blades. In practice, this alloy is known as MAR—M200 and is solid solution strengthened by chromium, tungsten and cobalt in the matrix and is also precipitation hardened by carbide and boride precipitates at the grain boundaries.
Unlike iron-based alloys, most heat-treatable alloys do not experience a ferrite transformation. In these alloys, the nucleation at the grain-boundaries often reinforces the structure of the crystal matrix. These metals harden by precipitation. Typically a slow process, depending on temperature, this is often referred to as "age hardening". [6]
This microstructure gives the steels a low yield strength, high rate of work hardening, and good formability. [1] Microalloyed steels: Steels which contain very small additions of niobium, vanadium, and/or titanium to obtain a refined grain size and/or precipitation hardening. A common type of micro-alloyed steel is improved-formability HSLA.
Precipitation hardening (also called age hardening) is a process where a second phase that begins in solid solution with the matrix metal is precipitated out of solution with the metal as it is quenched, leaving particles of that phase distributed throughout to cause resistance to slip dislocations. This is achieved by first heating the metal ...
SAE Type 630 stainless steel (more commonly known as 17-4 PH, or simply 17-4; also known as UNS S17400) is a grade of martensitic precipitation hardened stainless steel. It contains approximately 15–17.5% chromium and 3–5% nickel, as well as 3–5% copper. [1] The name comes from the chemical makeup which is approximately 17% chromium and 4 ...