Secondary phase, heat treatment

[mattyboson12]

"Precipitation hardening is a heat treatment that distributes secondary phases more evenly in an alloy..." What does it mean by a secondary phase?

 

[Astronuc]

"Precipitation hardening is a heat treatment that distributes secondary phases more evenly in an alloy..." What does it mean by a secondary phase?

A second phase or secondary phase has a different stoichiometry (composition) and microstructure than the primary phase of an alloy. Second phases are usually intermetallic compounds.

For example in nickel superalloys, Al and Ti form nickel aluminides or titanides.

http://en.wikipedia.org/wiki/Nickel_aluminide

http://en.wikipedia.org/wiki/Superalloy

 

[mattyboson12]

Thank you