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

摘要

We report uniaxial tensile studies of monocrystalline cylindrical Pd50Pt50 bimetallic alloy nanowire (NW) (11.67 angstrom diameter x 101.14 angstrom length) subjected to strain rates of 1%, 3%, 5%, 8% and 10% ps (1) and temperatures of 100 K, 300 K, 500K and 700K 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 thatNWis 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.