Critical conditions were determined for the intrinsic transformation of a vacancy Frank loop into a stacking fault tetrahedron in a face-centred cubic metal by using the molecular dynamics method. It was found that a stacking fault tetrahedron could be formed from the scalene hexagonal vacancy Frank loops of a wide range of sizes due to the dissociation of dislocations. The dynamic process in which vacancy and interstitial faulted Frank loops transformed into perfect loops was also found by applying an external shear stress or by raising the temperature. The simulation results clearly revealed the important role of temperature in the unfaulting mechanism of an interstitial Frank loop.

Molecular Dynamics Study on the Formation of Stacking Fault Tetrahedra and Unfaulting of Frank Loops in FCC Metals. T.Kadoyoshi, H.Kaburaki, F.Shimizu, H.Kimizuka, S.Jitsukawa, J.Li: Acta Materialia, 2007, 55[9], 3073-80