The shapes of edge dislocation loops in β-NiAl were studied. These loops had {001} habit planes, <001> Burgers vectors and exhibited two distinct forms. One of these was roughly square, with segments nearly parallel to <010>; this corresponded to the equilibrium shape calculated on the basis of elastic anisotropy. The other form consisted of segments aligned accurately parallel to <110>, which was expected to be elastically unstable. It was proposed that this second shape was stabilized by dissociation of the perfect dislocation into three partial dislocations on the intersecting {110} according to:

[001]  ¼[¯111] + ½[001] + ¼[1¯11].

On the Shape of Edge-Dislocation Loops in βNiAl. M.Aindow, A.Parthasarath, H.L.Fraser: Philosophical Magazine Letters, 1990, 62[5], 317-22