Tensile mechanical behavior and failure mechanisms of 3D orthogonal fabric reinforced aluminum matrix composites at high temperature

3D orthogonal fabric reinforced aluminum matrix composites were fabricated by the vacuum-assisted pressure infiltration techniques. The quasi-static tensile response, damage evolution and failure behaviors of the composites at high temperature (400 ℃) were investigated using numerical and experimental methods. Based on the yarn microstructure and fabric structure of the composites, microscale and mesoscale represent volume element (RVE) models were constructed respectively. According to the temperature-depended properties of the constituents, a microscale RVE based finite element model was established to predict the mechanical properties of the yarn at different temperatures. On this basis, the thermal residual stress and tensile behaviors of the composites at 400 ℃ were analyzed by the mesoscale RVE based finite element model. The results show that the inhomogeneous residual stress in the as-cast composites is related to the fabric structure, and the calculated residual stress agrees with that measured by nano-indentation method. At the high temperature, the residual stress is released and the matrix pocket and yarns are in compressive and tensile stress states, respectively. The homogenized tensile stress − strain curve is generally consistent with the experimental curves from the high temperature tensile tests, where the average value of elastic modulus, ultimate strength and elongation are 107.1 GPa, 657.1 MPa and 0.78%, respectively. In the initial tension stage, local damage zones occur in the matrix pocket and interface between the interlaced yarns, and local failure elements appear on the curve segment of binder yarns, but the composite exhibits a linear elastic response. The damage degree of matrix pocket is aggravated and the local interface debonding develops gradually with the increase of tensile strain. Meanwhile, the local failure zone emergences on the binder and weft yarns successively. As a result, nonlinear mechanical response begins to occur on the tensile curve. In the final stage, the expansion of failure zone on the warp yarns leads to a significant degradation of tangent modulus in the tensile curve, and the axial fracture of warp yarns induces the catastrophic fracture of the composites, accompanying with a dramatic drop of the tensile stress curve. Numerical simulation and fracture morphology indicate that the transverse cracking of weft and binder yarns results in a flat fracture surface, while the warp yarns, which are fractured under axial tension, exhibit a rugged fracture morphology. The microscopic fracture surface of warp yarn presents fiber pull-out and adjacency matrix tearing characteristic. © 2024 Central South University of Technology. All rights reserved.