Experiments on directional martensitic transformation in steel

This paper describes some preliminary experiments on the feasibility of producing steels with an aligned martensitic microstructure. The parent austenite is initially textured, following which the martensite habit plane “activity” is regulated by transforming under strain. An Fe-20 pct Ni-5 pct Mn alloy exhibiting a lowM _s temperature and a lath mar-tensite morphology was found suitable for producing aligned martensite. On heavy defor-mation this alloy developed a typical (123) [412] fcc texture. Subsequent annealing then produced a strong (001) [100] cube texture. Nearly 80 pct of the martensite formed was aligned when such a cube-textured specimen was strained 2.5 pet at 45 deg to the rolling direction followed by cooling under strain in liquid nitrogen to produce martensite. M. Khobaib and R. Quattrone, Formerly with the Construc-tion Engineering Research Laboratory, U.S. Army Corps of Engineers, Champaign, Illinois