Effects of Equal Channel Angular Pressing and Subsequent Annealing Treatment on Fe-Mn Damping Alloy
The damping capacity of Fe-Mn alloy which was subjected to equal channel angular pressing (ECAP) and subsequent annealed at different temperatures was measured by reversal torsion device. The microstructure was observed using the optical microscope and transmission electronic microscope. The results show that after ECAP and annealing at low temperature (600 ℃), there are lots of high-density dislocations and obvious banded structures, which inhibit the slip of damping resources and result in the low damping capacity. With increasing annealing temperature (700～800 ℃), high-density dislocations and banded structures gradually disappear. The amount of e martensite is larger than that of specimen without ECAP, and the martensite flakes are much refiner. The increasing interfaces per unit volume result in more damping resources on vibration, thus improve damping capacity remarkably. With further increasing annealing temperature (900～1 000 ℃), the martensite flakes grow up slightly, so the damping capacity of Fe-Mn alloy decreases, but it is still higher than that of specimen without ECAP.