Fabrication, Testing, and Analysis of Carbon-Carbon/Aluminum Bonded Joints With High Thermal Conductivity

S. Subramanian, F. Kustas, S. Rawal and E.T. Shinn

ABSTRACT

Bonded joints between carbon-carbon composites and aluminum were fabricated using a high temperature aluminum filled epoxy adhesive. Double notch shear tests were conducted to measure the bond strength of samples fabricated with high thermal graph 6000 (3-D) carbon-carbon composite were significantly higher than those with K-13 (2-D) carbon-carbon composites. In the thermal graph 6000 joints, failure occurs in carbon-carbon material at room temperature and in the adhesive bond at 4820 F. Finite element analysis results indicate high shear stresses, in the carbon-carbon material at room temperature and high shear stresses in the adhesive layer at 4820 F. Thermal cycling test on K-13/aluminum bonded joints between room temperature at 4820 F resulted in failures within 250 cycles. Residual bond strength degradation of over 50% was seen when samples cycles between 122 and 3920 F for 50 cycles. The bonded joints appear to have high thermal conductivity in the thickness direction due to the presence of aluminum particles in the adhesive material. The thermal graph 6000/aluminum joints possess higher through thickness thermal conductivity by virtue of the carbon fiber reinforcement in the thickness direction.