EFFECT OF MAGNETIZATION ON THE L2 ORDERING REACTION IN IRON-ALUMINUM ALLOYS

Abstract

It is found that the spontaneous magnetization of disordered iron‐aluminum alloys changes the mode of the L2₀ order‐disorder reaction from a second to a first degree transition. A new two‐phase field (α_m + α_2n) has been found in the composition range 22.3 at. % Al to 25 at. % Al and this is responsible for many of the magnetic anomalies of these alloys. The microstructure of alloys heat‐treated in the (α_m + α_2n)‐phase region can be controlled by an externally applied magnetic field which can also be used to determine quantitatively the ``antiphase'' boundary energy of the L2₀ structure.