Stress-induced martenstic phase transformation in Cu-Zr nanowires

Following the above paper titled as " Stress induced martenistic phase transformation in Cu-Zr nanowires" published in Materials Letters, Volume 63, Issue 15, 15 June 2009, Pages 1289-1292 by Vijay Kumar Sutrakar and D. Roy Mahapatra; a very recent paper titled as "Pseudoelasticity of Cu–Zr nanowires via stress-induced martensitic phase transformations" is published in Appl. Phys. Lett. 95, 021911 (2009); doi:10.1063/1.3183584 by  Q. Cheng, H A Wu, Y Wang and XX Wang.

The abstract of the paper is as follows:

Atomistic simulations were performed to investigate the pseudoelastic effects induced by martensitic phase transformation from body-centered cubic (B2) to body-centered tetragonal (BCT) lattice in Cu–Zr nanowires. The phase transformation occurs through nucleation and propagation of {100} twin boundary, which differs from the {101} twin boundary for B2 Ni–Al nanowires. During unloading, extension strain up to 45% can be fully recovered through inverse phase transformation. The BCT lattice has also been verified to be metastable for Cu–Zr nanowires with an energy analysis along the epitaxial Bain path. Our work implies Cu–Zr nanowires may be excellent functional components for nanoelectromechanical systems. ©2009 American Institute of Physics

Recently a Comment on “Pseudoelasticity of Cu–Zr nanowires via stress-induced martensitic phase transformations” [Appl. Phys. Lett. 95, 021911 „2009] by V K Sutrakar and D Roy Mahapatra has been published online. The abstract of the paper is given below, full paper can be download from  http://link.aip.org/link/?APPLAB/95/136101/1 Abstract: Recently, a novel stress-induced phase transformation in an initial 100 / 100 B2-CuZr nanowire has been reported for the first time [Sutrakar and Mahapatra, Mater. Lett. 63, 1289 2009]. Following this, a martenisitic phase transformation in Cu–Zr nanowire was shown [Cheng et al., Appl. Phys. Lett. 95, 021911 2009] using the same idea [Sutrakar and Mahapatra, Mater. Lett. 63, 1289 2009]. The pseudoelastic recovery of the bct phase of Cu–Zr by unloading has also been shown [Cheng et al., Appl. Phys. Lett. 95, 021911 2009]. They also tested the epitaxial bain path [Alippi et al., Phys. Rev. Lett. 78, 3892 1997] and reported that the bct phase in the nanowire is metastable, whereas the bulk counterpart is unstable. This aspect is re-examined in this comment with corrected results. © 2009 American Institute of Physics. doi:10.1063/1.3242021   Further the Response to Comment on “Pseudoelasticity of Cu–Zr nanowires via stress-induced martensitic phase transformations” [Appl. Phys. Lett. 95, 021911 „2009] by Cheng et al can be downloaded from http://link.aip.org/link/?APPLAB/95/136102/1 

Recently, a paper titled "Single and multi-step phase transformation in CuZr nanowire under compressive/tensile loading" is published in Intermetallics by Vijay Kumar Sutrakar and D Roy Mahapatra . The abstract of the paper is given below. Full paper can be downloaded from doi:10.1016/j.intermet.2009.11.006    

Abstract:

A novel stress induced martenistic phase transformation is reported in an initial B2-CuZr nanowire of cross-sectional dimensions in the range of 19.44 × 19.44–38.88 × 38.88 Å2 and temperature in the range of 10–400 K under both tensile and compressive loading. Extensive Molecular Dynamic simulations are performed using an inter-atomic potential of type Finnis and Sinclair. The nanowire shows a phase transformation from an initial B2 phase to BCT (body-centered-tetragonal) phase with failure strain of 40% in tension, whereas in compression, comparatively a small B2 → BCT phase transformation is observed with failure strain of 25%. Size and temperature dependent deformation mechanisms which control ultimately the B2 → BCT phase transformation are found to be completely different for tensile and compressive loadings. Under tensile loading, small cross-sectional nanowire shows a single step phase transformation, i.e. B2 → BCT via twinning along {100} plane, whereas nanowires with larger cross-sectional area show a two step phase transformation, i.e. B2 → R phase → BCT along with intermediate hardening. In the first step, nanowire shows phase transformation from B2 → R phase via twinning along {100} plane, afterwards the nanowire deforms via twinning along {110} plane which cause further transformation from R phase → BCT phase. Under compressive loading, the nanowire shows crushing along {100} plane after a single step phase transformation from B2 → BCT. Proper tailoring of such size and temperature dependent phase transformation can be useful in designing nanowire for high strength applications with corrosion and fatigue resistance.