The piezoelectric ultrasonic composite oscillator technique (PUCOT) has been used at temperatures up to 638 K and at 80 kHz to measure dynamic Young's modulus E, mechanical damping or internal friction Q⁻¹ and strain amplitude ϵ in Al/SiC^w and Al/Sic^p. For four adjacent specimens from one sheet of 6061 Al/SiC^p E-values varied in the range 114–119 GPa at room temperature. The composition dependence of the modulus followed E = 68.6 + 2.2X with R = 0.95 (E is in GPa and X in volume percent SiC). The temperature dependence of the dynamic modulus followed E = 138.7 − 0.11T with R = 0.98 (E is in GPa and T in Kelvin). The amplitude dependence of Q⁻¹ for 6061 Al/SiC^w revealed a damping peak at ϵ = 10⁻⁶. An analysis of the internal friction data in terms of a damping theory yielded values for the minor pinning length of dislocation lines and the density of mobile dislocations. The results are discussed in terms of the microstructure.