The nature and structure of the Sigma Phase in Transition Alloys

The compositional limits of Sigma phase in various binary and ternary systems and relevant characteristics of such systems have been critically discussed on the basis of different hypotheses advanced to explain the formation and structural features of Sigma phase. The inherent characteristics of Sigma phase and its effect on the mechanical properties of steels have also been dealt with. (Dr. E.G. Ramachandran, Assistant Director; Mr. L.J. Balasundaram, Senior Scientific Officer, National Metallurgical Laboratory, Jamshedpur)