A terrace/ledge nucleation model was used to study the relationship between the degree of undercooling and the formation probability of twins or stacking-faults. The model was consistent with experimental results for rapidly solidified 2-phase alloys, and indicated that - at an undercooling of 37 to 55K - twins or stacking-faults first formed in the Ag-rich solid solution. A larger undercooling caused the formation of twins or stacking faults in Cu-rich solid solutions. The degree of undercooling which was required for defect formation could be related to the stacking fault or twin boundary energy of a material.

Modelling the Formation of Twins and Stacking Faults in the Ag-Cu System. K.Han, J.P.Hirth, J.D.Embury: Acta Materialia, 2001, 49[9], 1537–40