Enhancing damping capacity and mechanical properties of Al-Mg alloy by high strain rate hot rolling and subsequent cold rolling

Abstract

The damping capacity of high Mg alloyed Al-Mg alloy (Al-9.2Mg-0.8Mn-0.2Zr-0.15Ti) prepared by high strain rate hot rolling (HSRR) and subsequent cold rolling (CR) are carefully studied. Both the strain amplitude dependent internal friction (ADIF) at room temperature and the temperature dependent internal friction (TDIF) at elevated temperature are detected by a dynamic mechanical analyzer (DMA). The results indicate that the subsequent cold rolling can significantly improve the damping capacity of the alloy. The as-CRed alloy exhibits higher strength and better damping capacity than the as-HSRRed alloy, with the ultimate tensile strength (UTS) of 606 ± 6 MPa, the elongation to rupture of 11.6 ± 0.6% and the Q-1 value of 0.019 at room temperature with the strain of 1 × 10-3 and the frequency of 1 Hz. The room temperature damping of the as-CRed alloy is mainly ascribed to the low stacking fault energy (SFE), the high dislocation density and the finer broken second phase particles. Moreover, the as-CRed alloy also presents excellent high temperature damping, with the maximum Q-1 value of 0.212 ± 0.003 at 361 ℃ with the frequency of 1 Hz. The relatively high damping capacity of the cold rolled sheet for a given frequency and temperature can be attributable to the special microstructure characteristics including the high dislocation density, the elongated lamellar grains with shear bands and the high fraction of LAGBs.