Damage evolution in AA2124/SiC metal matrix composites under tension with consecutive unloadings

Abstract

Nonlinear properties of metal matrix composites (MMCs) are studied. The research combines results of loading–unloading tensile tests, microstructural observations and numerical predictions by means of micromechanical mean-field models. AA2124/SiC metal matrix composites with SiC particles, produced by the Aerospace Metal Composites Ltd. (AMC) are investigated. The aluminum matrix is reinforced with 17% and 25% of SiC particles. The best conditions to evaluate the current elastic stiffness modulus have been assessed. Tensile tests were carried out with consecutive unloading loops to obtain actual tensile modulus and study degradation of elastic properties of the composites. The microstructure examination by scanning electron microscopy (SEM) showed a variety of phenomena occurring during composite deformation and possible sources of elastic stiffness reduction and damage evolution have been indicated. Two micromechanical approaches, the incremental Mori–Tanaka (MT) and self-consistent (SC) schemes, are applied to estimate effective properties of the composites. The standard formulations are extended to take into account elasto-plasticity and damage development in the metal phase. The method of direct linearization performed for the tangent or secant stiffness moduli is formulated. Predictions of both approaches are compared with experimental results of tensile tests in the elastic–plastic regime. The question is addressed how to perform the micromechanical modelling if the actual stress–strain curve of metal matrix is unknown.

Sustainability in the Manufacturing of Eco-Friendly Aluminum Matrix Composite Materials

“…Similar observations were made by Cai et al, achieving a Young's modulus increase of approximately 21 GPa with 55% SiC addition to the aluminum matrix [29]. Rutecka et al obtained a Young's modulus value of 110 GPa for the AA2124 matrix composite reinforced with 25% SiC [30]. Kumar et al [31] investigated the effect of the weight fraction of SiC on the mechanical and tribological properties of Al-5.6Zn-2.2Mg-1.3Cu matrix composites.…”