Annealing twin boundaries were important in the evolution of grain boundary engineered materials. The development of annealing twins in face-centered cubic metals was a function of stacking fault energy and a number of other factors. It was observed that annealing heavily deformed Cu under shear stress tends to promote the formation of twin boundaries.

The Role of Shear Stress in the Formation of Annealing Twin Boundaries in Copper. D.P.Field, R.C.Eames, T.M.Lillo: Scripta Materialia, 2006, 54[6], 983-6