Mesomechanical Numerical Modeling of the Stress-Strain Localization and Fracture in an Aluminum Alloy with a Composite Coating.

A numerical analysis of plastic strain localization and fracture in an aluminum alloy with a composite aluminum (Al) - titanium carbide (TiC) coating providing oxidation protection is presented. Boundary-value problems in plane strain and three-dimensional formulations are solved numerically by the finite-difference and finite-element methods' respectively. The Al-TiC interface geometry corresponds to the configuration found experimentally and is accounted for explicitly in calculations. An algorithm to build a 3D finite-element model of TiC particles is developed. To simulate the mechanical response of the aluminum substrate and composite coating' use was made of an elastic-plastic model with isotropic strain hardening and a fracture model taking into account crack initiation and growth in the regions experiencing tensile stresses. Local regions of bulk tension are shown to arise near the interfaces even under simple uniaxial compression of the coated material' which controls the mechanisms of plastic strain and fracture localization at the mesoscale level. The role of technological residual stresses is revealed. [ABSTRACT FROM AUTHOR]