Structural, thermodynamic and mechanical properties of Zr-based binary nanowires (ZrCu and Zr2Ni) by molecular dynamics

We present molecular dynamics simulation results of two representative cases of nanowires (NWs) of binary alloys, a glass former (ZrCu) and an alloy that becomes amorphous under chemical substitution of its elements (Zr2Ni). The simulations were based on semiempirical potential models in analogy to the tight-binding scheme in the second moment approximation. We explored the structural characteristics of NWs of various sizes, and we determined several quantities like melting points, strain-stress curves and Young's modulus. We found that for all NWs, the Zr terminations are energetically favored, while Zr2Ni NWs adopt rounded cross-sectional shapes and ZrCu, octagonal. From the obtained results, it is established that most of the NW properties differ substantially from those exhibited by their bulk counterparts; e.g., lower melting points and greater yield strengths, while under tensile strain they exhibit clear brittle character. In addition, it is found that their mechanical response to deformation is not very sensitive to the imposed strain rates. (C) 2006 Elsevier B.V. All rights reserved.