A Micromechanics-Based Elastoplastic Model for Amorphous Composites With Nanoparticle Interactions

A constitutive model is proposed to investigate the strengthening mechanism and the relationship between nanostructures and effective mechanical properties of the aluminum-based amorphous nanocomposites. A continuum micromechanics-based, three-phase composite model comprises of Al particles, rare-earth enriched interlayers, and the amorphous aluminum matrix. The local stress field and deformation are formulated based on the concept of eigenstrain and equivalent inclusion method with consideration of both the particle-interlayer-matrix interaction and the particle-particle interaction. An ensemble-volume averaging technique is conducted to obtain the overall elastoplastic constitutive behavior for amorphous nanocomposites with randomly distributed spherical nanoparticles. Explicit expressions of the effective elastic stiffness and yield function in terms of the constituent properties and nanostructures are obtained. The effective elastoplastic stress-strain curves for uniaxial loading and the initial yield surfaces for axisymmetric loading are calculated. Simulations are conducted to investigate the effects of the particle size and pairwise particle interaction on the effective mechanical properties.