The dominant occurrence of the b = a(001) prismatic edge dislocation loops in iron and iron-based alloys irradiated at temperatures approaching 500C was a striking anomaly distinguishing iron and its alloys from other body-centered cubic metals. It was surprising that the a(001) dislocation loops form at all, since there was an alternative b = a/2(111) dislocation loop configuration that, according to the conventional isotropic treatment of elasticity, had a lower self-energy. Here, the magnetic aspect of the problem was highlighted and the fundamental link between the α–γ phase transition was noted; the elastic anisotropy of iron, which was particularly significant at elevated temperatures, and thermal magnetic fluctuations.

The Magnetic Origin of Anomalous High-Temperature Stability of Dislocation Loops in Iron and Iron-Based Alloys. S.L.Dudarev, P.M.Derlet, R.Bullough: Journal of Nuclear Materials, 2009, 386-388, 45-8