A transition was reported in the dislocation microstructure of pure Fe produced by heavy-ion irradiation of thin foils, which took place between irradiation temperatures of 300 and 500C. At Tirr ≤ 400C, the microstructure was dominated by round or irregular non-edge dislocation loops of interstitial nature and with Burgers vectors b = ½<111>, although interstitial <100> loops were also present; at 500C only rectilinear pure-edge <100> loops occurred. At intermediate temperatures there was a gradual transition between the two types of microstructure. At temperatures just below 500C, mobile ½<111> loops were seen to be subsumed by sessile <100> loops.

The Temperature Dependence of Heavy-Ion Damage in Iron: a Microstructural Transition at Elevated Temperatures. Z.Yao, M.L.Jenkins, M.Hernández-Mayoral, M.A.Kirk: Philosophical Magazine, 2010, 90[35-36], 4623-34