Question

Explain age hardening treatment?

Answer 1

Age hardening, also known as precipitation hardening, is a type of heat treatment that is used to impart strength to metals and their alloys. It is called precipitation hardening as it makes use of solid impurities or precipitates for the strengthening process. The metal is aged by either heating it or keeping it stored at lower temperatures so that precipitates are formed. The process of age hardening was discovered by Alfred Wilm.

Malleable metals and alloys of nickel, magnesium and titanium are suitable for age hardening process. Through the age hardening process the tensile and yield strength are increased. The precipitates that are formed inhibit movement of dislocations or defects in the metals crystal lattice. The metals and alloys need to be maintained at high temperatures for many hours for the precipitation to occur; hence this process is called age hardening.

This article will look into the techniques of age hardening and their applications.

Answer 2

In metallurgy, age hardening is a heat treatment technique used to increase the hardness of an alloy by a relatively low-temperature heat treatment that causes precipitation of components or phases of the alloy from the supersaturated solid solution.

It is used to increase the tensile and yield strength of materials, including most alloys of aluminum, magnesium/titanium/nickel and some stainless steel. In superalloys, it is known to cause yield strength anomaly, providing excellent high-temperature strength.

Age hardening is also known as precipitation hardening.