Influence of aluminum foam core thickness on the mechanical and thermal properties of epoxy–carbon fiber mat sandwich composites

This study examines the influence of aluminum foam thickness on the mechanical and thermal characteristics of epoxy resin-based sandwich composites reinforced with carbon fiber matting. Four samples (S1–S4) were produced: S1 comprised one layer of pure carbon fiber mat, while S2–S4 consisted of three layers of carbon fiber mat mixed with two layers of aluminum foam at thicknesses of 0.5 mm (S2), 1 mm (S3) and 1.5 mm (S4). The results indicate that the use of aluminum foam significantly improves mechanical characteristics relative to the pure carbon fiber sample. Sample S3, with 1 mm thick aluminum foam, attained the maximum tensile strength (128.7 MPa) and impact strength (10.2 J/m2), exhibiting the best balanced mechanical performance. The flexural strength and hardness of the sandwich samples increased, with the maximum hardness observed in S3 (246 HV). Thermal conductivity diminished with increasing foam thickness, varying from 1.6 W/m•K in S1 to 0.9 W/m•K in S4. This situation signifies a compromise between mechanical strength and thermal conductivity. The findings indicate that employing aluminum foam of suitable thickness can markedly boost the performance of sandwich composites in applications necessitating lightweight materials with superior mechanical characteristics and regulated thermal behavior.