Wiktionary
gamma iron
alt. (context metallurgy English) An allotropic form of iron which is stable at high temperatures. It is used in the manufacture of Austenite. n. (context metallurgy English) An allotropic form of iron which is stable at high temperatures. It is used in the manufacture of Austenite.
WordNet
gamma iron
n. a nonmagnetic allotrope of iron that is the basis of austenite; stable between 906 and 1403 degrees centigrade