Effect of carbon fiber and diffusion layer thickness on tissue properties of Al-Mg-Ti laminated composites

Carbon fiber-reinforced Al-Mg-Ti laminated composites were prepared by vacuum hot-press diffusion technique and "foil-fiber-foil" method using 1060 pure aluminum, TC4 titanium alloy, AZ31 magnesium alloy and nickel-plated carbon fiber woven fabric as raw materials. The effect of Al-Mg diffusion layer thickness on the material tissue properties was analyzed by controlling the Al-Mg holding time, and the strengthening mechanism of carbon fiber was discussed. The phase composition, element distribution and crack extension morphology of the composites were analyzed by X-ray diffraction (XRD), energy spectrum (EDS) analyzer and scanning electron microscopy (SEM), and the flexural strength and impact toughness of the composites were tested. The results show that the thickness of diffusion layer of carbon fiber-reinforced Al-Mg-Ti laminated composites increases with the increase of holding time, and the mechanical properties show a trend of increasing and then decreasing, and the carbon fiber absorbs a large amount of fracture energy through fiber debonding, fiber pull-out and fiber splitting, which plays a significant toughening effect. The mechanical properties of the composites are optimal at the hot pressing temperature of 640 ℃ for 2 h for Al-Ti and 440 ℃ for 8 h for Al-Mg, with flexural strength of 380 MPa and impact toughness of 26.2 J/cm2, which are increased by 10.8% and 30.3% respectively, relative to the matrix flexural strength and impact toughness.