Elastic properties of Fe95-yNb2Mo2Cu1Siy-xBx (x=5-8, y=20-26) at % amorphous alloys

Abstract

Amorphous materials exhibit complex atomic structures characterized by the absence of long-range order, in contrast to the well-defined periodicity of crystalline materials. This structural complexity is further pronounced in compositions such as FeMCuSiB (M = Nb, Mo, W and Ta), which incorporate elements with varying atomic radii and valencies. The Young's modulus of structures generated using traditional methods, such as melt-quenching and random packing, shows poor agreement with experimental data. In this study, we employ hybrid methods for generating the structures, which involve randomly packing elements without overlap, followed by thermalization at room temperature using Ab-initio Molecular Dynamics simulations. The Young's modulus evaluated from these structures aligns well with values measured using Dynamic Mechanical Analysis. Additionally, we utilize these structures to determine other elastic moduli including the bulk modulus and tetragonal shear modulus and find that the obtained values are consistent with the expected range for these compounds. We attribute the improved accuracy to a more representative approximation of the amorphous structure and the direct application of energy-strain relationships, rather than stress-strain relationships, for elastic moduli determination. Our methodology facilitates reliable predictions of the physical properties of amorphous materials and contributes to the design of FeMCuSiB (M = Nb, Mo, W and Ta) alloys with enhanced mechanical properties.