Search

With first-principles virtual-crystal approximation calculations, we systematically investigate the geometric and electronic structures as well as the phase transition of lead zirconate titanate (PbZr1-xTixO3 or PZT) as a function of Ti content for the whole range of 0 ⩽ xTi ⩽ 1. It can be found that, with the increase of the Ti content, the PbZr1-xTixO3 solid solutions undergo a rhombohedral-to-tetragonal phase transition, which is consistent with the experimental results. In addition, we also show the evolution in geometric and electronic structures of rhombohedral and tetragonal PbZr1-xTixO3 with the increasing content of Ti. [ABSTRACT FROM AUTHOR]

Grain boundary activity in nanocrystalline Al under an indenter is studied by using a multiscale method. It is found that grain boundaries and twin boundaries can be transformed into each other by emitting and absorbing dislocations. The transition processes might result in grain coarsening and refinement events. Dislocation reflection generated by a piece of stable grain boundary is also observed, because of the complex local atomic structure within the nanocrystalline Al. This implies that nanocrystalline metals might improve their internal structural stability with the help of some special local grain boundaries. [ABSTRACT FROM AUTHOR]