Microstructure and Damping Behavior of Continuous W-Core-SiC Fiber-Reinforced Aluminum Matrix Composites

The damping behavior of continuous SiC fiber reinforced aluminum matrix (SiC_f/Al) composite is still poorly understood. This paper examined the temperature dependence and strain amplitude dependence of damping capacities in 30 vol% SiC_f/Al composites including SiC_f/2024Al, SiC_f/6061Al and SiC_f/AlFe5Si2 composites, and the unreinforced aluminum alloys. Microstructure characterization was performed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron backscattered diffraction (EBSD) and X-ray diffraction (XRD) analysis to investigate the operative damping mechanisms in the SiC_f/Al composites. The results show that uniform dispersion of SiC_f and good interface bonding were achieved with these SiC_f/Al composites. The damping capacity and dynamic modulus of these composites were greatly improved as compared with that of the unreinforced aluminum alloys. The dominant damping mechanisms for SiC_f/Al composites were dislocation damping at low temperatures (< 150 ℃), and grain boundary damping and interface damping at high temperatures (> 150 ℃). This work indicated that the SiC_f/AlFe5Si2 composite simultaneously exhibited good damping capacity and high dynamic modulus, having potential for aerospace applications.