The effect of temperature and strain rate on the interaction between an edge dislocation and an interstitial dislocation loop in α-iron

The influence of temperature, T , and strain rate, ˙ε, on the reaction between the 1/2[111](1¯10) edge dislocation line and a periodic row of 4 nm interstitial dislocation loops with Burgers vector b = 1/2[1¯11] in α-Fe has been investigated by means of molecular dynamics, using a potential developed recently for body centred cubic Fe (Ackland et al 2004 J. Phys.: Condens. Matter 16 1). A dislocation segment with b = [010] is formed by favourable reaction in all cases: it is sessile in the (1¯10) glide plane and leads to the formation of a screw dipole on the line under increasing stress. The mechanism controlling line breakaway and the corresponding critical stress depend mainly on T rather than ˙ε. At high T (300 and 600 K here) the length of the screw dipole is short (