ABSTRACT

Interactions between edge dislocations and a Sigma 11 symmetrical tilt grain boundary (GB) in face-centred cubic metals of Ni and Al are studied via a quasicontinuum method (QCM). A variety of embedding atom method potentials are used, and the results are compared to previous studies of Cu [W.S. Yu, Z.Q. Wang, Acta Mater., 60 (2012) 5010]. Different potentials do not significantly affect the edge dislocation-GB interactions in these metals. Edge dislocations can easily transmit across grain boundaries in Ni and Cu, even for a single incoming dislocation. However, slip-transmission in Al occurs only after the GB absorbs many incoming dislocations. Stable nucleation of grain boundary dislocations (GBD) in Cu and Ni plays an important role in the slip-transmissions. The slip transmission in Al is found to be difficult due to the metastable nucleation of GBD. The incoming leading and trailing partials in Al are absorbed together by the GB because of the larger values of gamma(sf)/mu b(p) (mu, b(p) and gamma(sf) are the shear modulus, magnitude of Burgers vector of a partial dislocation and the stable stacking fault (SF) energy, respectively). The parameter R = (gamma(usf) - gamma(sf))/mu b(p) (gamma(usf) as the unstable SF energy) [Z.H. Jin et al., Acta. Mater. 56 (2008) 1126] incorporates gamma(sf)/gamma(usf) and gamma(sf)/gamma b(p), and can be used to measure the slip transmission ability of an edge dislocation in these metals. It is also shown that certain loading conditions can help enhance the nucleation of GBDs and GBD dipoles in Al, such that the incoming, leading and trailing partial dislocations can be absorbed separately.