Homogeneous nucleation of dislocation loops in nanocrystalline metals and ceramics

✍ Scribed by M.Yu. Gutkin; I.A. Ovid’ko

• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 574 KB
• Volume: 56
• Category: Article
• ISSN: 1359-6454
• DOI: 10.1016/j.actamat.2007.12.004

✦ Synopsis

A special mechanism of dislocation nucleation in deformed nanocrystalline metals and ceramics is theoretically described. The mechanism represents non-local homogeneous nucleation of a nanoscale loop of ''non-crystallographic" partial dislocation whose Burgers vector magnitude continuously grows during the nucleation process. The dislocation loop nucleation is accompanied by nucleation and evolution of a generalized stacking fault bounded by the loop. It is shown that the special mechanism can effectively produce nanoscale loops of lattice dislocations in nanocrystalline metals (Al, Ni) and ceramics (3C-SiC) deformed at high mechanical stresses achieved in shock-wave and indentation load regimes.