By combining weak-beam and conventional dark-field transmission electron microscopy, the critical behavior of antiphase boundaries close to the second-order D03-B2 order-disorder transition was studied. The weak-beam technique was particularly accurate, since the intensity of the antiphase boundary fringes decreased exponentially when the width of the boundaries, which was proportional to the correlation length, increased. The measured critical exponent, of 0.64, was in good agreement with theory, as well as with scattering experiments for the B2 phase.

Critical Behavior of Antiphase Boundaries in Fe3Al Close to the D03 → B2 Phase Transition D.Le Floch, A.Loiseau, C.Ricolleau, C.Barreteau, R.Caudron, F.Ducastelle, J.M.Pénisson: Physical Review Letters, 1998, 81[11], 2272-5