Determination of glass forming ability and mechanical properties of AlZr₃ bulk metallic glass using MD simulations

Abstract Molecular dynamics (MD) simulations have been carried out with 2nn-MEAM potentials to achieve AlZr 3 bulk metallic glass (BMG) and to characterise its mechanical properties under uniaxial tensile loading. The AlZr 3 amorphous alloy is prepared from the molten state of AlZr 3 intermetallic by rapid quenching process with a cooling rate of 10 12 K s −1 . By deploying different criteria, such as: glass forming ability, radial distribution function and Voronoi tessellation analysis, the formation of AlZr 3 BMG is marked. To understand the effect of strain rate and temperature on various mechanical properties of the BMG, it is subjected to uniaxial tensile loading at strain rates varying from 0.0005 ps −1 to 0.05 ps −1 and temperatures in the range of 100 K to 1000 K respectively. It is observed that with increase in strain rate, the Young’s modulus of the BMG remained unperturbed whereas the yield stress, yield strain, ultimate tensile strength increased. All of the above properties decreased with increase in temperature. For comparison, the mechanical properties of AlZr 3 intermetallic under varying strain rates are also investigated. In the latter case, with increase in strain rate, substantial decrease in Young’s modulus is observed, whereas very minute change in yield stress, yield strain and ultimate tensile strength is noticed. The Young’s modulus and ultimate tensile strength of the BMG are found to be lesser than those of the intermetallic. Furthermore, distribution of local atomic shear strain is used to monitor the development of shear transition zones (STZ) and formation of shear bands during the tension in the BMG.