Thermal Expansion Behavior of Al/CFRP Multi-Layered Hybrid Composite Materials

Abstract

The thermal expansion behavior of the hybrid materials built up from many thin Al (aluminum IN30) sheets and unidirectional CFRP prepreg layers (fiber volume content 60%) was investigated theoretically and experimentally. The linear thermal expansion coefficients in three mutual directions, parallel to fibers (α_X^H), perpendicular to fibers and parallel to laminate (α_Y^H), perpendicular to laminates (α_Z^H), were derived from analyzing the two-layer structural model. These anisotropic linear thermal expansion coefficients were measured by the interferometric technique from room-temperature to 150°C. α_X^H and α_Y^H had little temperature dependent behavior and their values were almost constant. The value of α_Z^H was also almost constant between room-temperature and 80°C, but at higher temperatures than 80°C they increased remarkably with increasing temperature. The constant values of α_X^H, α_Y^H, α_Z^H were about 7×10^-61/°C, 28×10^-61/°C, 34×10^-61/°C, respectively. The average value of α_X^H was less than 30% that of monolithic aluminum. The estimated values agreed well with the experimental ones. But in the case of a thickly layered hybrid material, it is necessary to consider a shearing deformation of adhesive layers for the analysis of thermal expansion behavior.