Martensitic transformations in Ag-Au bimetallic core-shell nanoalloys

Combining the Gupta potential and bond order analysis in a molecular dynamics simulation, a martensitic transformation is observed in the 147-atom AucoreAgshell nanostructure at 328 K. The response time for this transformation is about 7 ps at 350 K. In pure gold clusters, it was previously thought that a similar solid-to-solid transformation is a prelude to melting transitions. In the present case, atomic pathway snapshots show that the heating energy is used to overcome the energy barrier for initiating the spontaneous process. The subsequent twist-deformation propagation and termination are clearly observed. (c) 2008 American Institute of Physics.