The formation of stacking fault tetrahedra in Al and Cu II SFT growth by successive absorption of vacancies generated by dipole annihilation

The growth of stacking fault tetrahedra (SFTs) resulting from dipole annihilation is investigated by molecular dynamics (MD) simulations The atomistic processes Involved during growth immediately after nucleation are studied Analyzed for up to three vacancies the site preference of vacancies on a perfect SFT favors vacancy segregation at edge centers and corners in Cu and Al, respectively The formation of small sized SFTs does not require a prior triangular Frank loop Instead, SFT growth involves vacancies and their clusters agglomerating as complex faceted configurations which assisted by accelerated vacancy migration along SFT edges rearrange into near perfect and perfect SFTs SFT growth by the ledge mechanism is investigated in Part III (C) 2010 Acta Materialia Inc Published by Elsevier Ltd All rights reserved