Dictionary
mar•tens•ite
Pronunciation: (mär'tn-zīt"), [key]—
n. Metall.
a metastable microconstituent of any of various forms of carbon steel, produced by undercooling sufficiently below the normal transformation temperature, esp. a hard, brittle product of the decomposition of austenite, produced in this way.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.