Precipitation hardening Vs Martensitic Transformation

[Cowkid]

hi everyone, i am try to figure out what is the differences of precipitation hardening and martensitic transformation as both are also considered as hardening mechanism??

 

[Astronuc]

Martenisitic transformation is very specific to the restructuring of the crystal structure in the Fe-C lattice. Precipitation hardening is more general, and involves other phases, e.g., intermetallic phases.

http://www.azom.com/article.aspx?ArticleID=2819

Precipitation hardening in alloys
http://nvl.nist.gov/pub/nistpubs/sp958-lide/014-015.pdf

 

[Enthalpy]

Martensitic transformation is specific to steel (and some exotic Ti alloys, named by analogy?), where the desired hard phase, martensite, is obtained through cooling (or through Si for spring steel and a few more) and needs quenching, brutally or not.

Precipitation hardening is the usual behaviour (Al, Cu, Ti, Mg, Ni, Co... based alloys) where tempering hardens the alloy.

Though, less common steel compositions are hardened by precipitation, some in martensitic phase, others in austenitic or in duplex phase. This hardening exists in C-rich as well as C-poor compositions.

Wiki would already tell a lot about that.