Tensile behavior and failure mechanism of 3D woven fabric reinforced aluminum composites

This paper aims to study the mechanical behavior and the complicated failure mechanism of a novel Al matrix composites reinforced with 3D orthogonal woven carbon fiber. The quasi-static tensile behavior, local stress response and progressive failure process are investigated via numerical and experimental approach. According to the microstructure at fiber and yarn scale, microscopic and mesoscopic finite element models were established to carry out multiscale simulation. The calculated tensile stress-strain curve is basically in accordance with the experimental curves, where the elastic moduli, tensile strength, and elongation are 118.6 GPa, 777.3 MPa and 0.84%, respectively. Local stress distribution of the matrix pocket and yarns exhibits apparent periodicity and heterogeneity, which is related to the specific fabric architecture. Interface debonding induces the local damage of matrix alloy and transverse cracking of binder and weft yarns successively, resulting in nonlinear response of the tensile curves. The catastrophic rupture of the composites is caused by the axial fracture of warp yarns that resulted from the combination of matrix failure and transverse yarns cracking. The fracture morphology of binder and weft yarns is flat and that of warp yarns exhibits limited fiber pull-out, which can be interpreted by the predicted failure mode. Based on the validated model, the influence of fabric structure parameters on the macroscopic properties was further evaluated. The results indicate that the increase of warp or weft density could improve the tensile strength and elastic modulus, but the tensile elongation decreases with the increase of weft density.