Regular Article

Superplastic Pd₅₀Pt₅₀ monocrystalline bimetallic alloy nanowire: a molecular dynamics simulation study

¹ Department of Metallurgical and Materials Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, West Bengal, India
² Computational Materials Engineering Group, Department of Metallurgical and Materials Engineering, National Institute of Technology Rourkela, Rourkela 769008, Odisha, India
³ Metallurgical Engineering Department, Government College of Engineering, Salem 636011, Tamil Nadu, India

^⁎ e-mail: yedlan@nitrkl.ac.in

Received: 26 July 2016
Received in final form: 22 October 2016
Accepted: 15 November 2016

Abstract

We report uniaxial tensile studies of monocrystalline cylindrical Pd₅₀Pt₅₀ bimetallic alloy nanowire (NW) (11.67 Å diameter × 101.14 Å length) subjected to strain rates of 1%, 3%, 5%, 8% and 10% ps⁻¹ and temperatures of 100 K, 300 K, 500 K and 700 K using molecular dynamics simulations. The tensile test is carried out along y-axis [0 1 0] with periodic boundary conditions and non-periodic along x-axis and z-axis. Dissipative mechanisms such as dislocations, partial dislocations and stair rod dislocations are also identified during deformation. It is found that NW is sensitive to strain rates and temperatures and exhibits superplastic behavior with strain >100% at higher strain rates. Young's modulus is found to be sensitive to strain rate and temperature and is about 25% less that of bulk value at strain rates >5% ps⁻¹ and at 300 K. Yield strength increases linearly with strain rate and decreases with increase in temperature as expected. Crystalline to amorphous-phase transformations take place at strain rates >5% ps⁻¹ and could be the reason behind large plastic strain. The calculated mechanical properties of NWs will be useful in devices applicable to sensing and catalysis.