Effect of porosity on damping behavior of aluminum matrix-fly ash composites
(1.黑龙江省哈尔滨市哈尔滨工业大学金属基复合材料工程技术中心
2.Center for Metal Matrix Composites Engineering Technology,Harbin Institute of Technology, Harbin 150001, China)
2.Center for Metal Matrix Composites Engineering Technology,Harbin Institute of Technology, Harbin 150001, China)
Abstract: The hollow sphere fly ash/6061Al composite with about 43% porosity in volume fraction (produced by the addition of hollow sphere fly ash particles) was fabricated by squeeze casting technique. Using the same technique, the fly ash/7075Al composite with all the porosity in hollow sphere fly ash infiltrated by molten aluminum was fabricated for partially studying the effect of porosity on the damping behavior of the fly ash/Al composites. The resonant damping capacity of the ‘porous’ fly ash/6061Al composite reached (20.2?26.9)×10?3 and was about 8 times of the value tested by forced vibration method (in the frequency range 0.2?2 Hz). However, the damping capacity of the as-received 6061Al and the ‘dense’ fly ash/7075Al composite were consistent by the two testing methods and were in the range of (1.1?7.7)×10?3. The effect of temperature on the damping behavior of the materials was also studied. The related damping mechanisms have also been discussed in light of data from the characterization of microstructure and damping capacity. Due to the inferior mechanical properties of the fly ash particles, the tensile strength of the FA/Al composites was lower than that of the corresponding aluminum alloy matrix and was 70.1 MPa and 180.6 MPa for the ‘porous’ fly ash/6061Al and ‘dense’ fly ash/7075Al composite, respectively.
Key words: metal matrix composites; porous material; fly ash; damping properties