Effect of ECAP on damping capacity of pure aluminum L2

Industrial pure aluminum L2 billets were pressed by equal channel angular pressing (ECAP) using a solid die made of H13 steel with an internal angle (φ) of 90° between the vertical and horizontal channels and a curvature angle (ψ) of 30°. The damping capacity was measured by the cantilever beam technique. The experimental results show that ECAP could improve the microstructures and refine the grains of L2 alloys efficiently. The alloys with coarse grains of 1mm in diameter can be refined to quasi-equiaxed grains with 1 μm in diameter by ECAP for 4 passes. The damping capacity Q^-1 of the alloy can also be improved with ECAP and come to the maximum value 3.1 × 10^-3 at equivalent strain of 3.8 × 10^-5 after ECAP for 4 passes, which is 80 percent higher than that of the alloy before ECAP. The damping capacity is dependence of vibration amplitude, and increases as the increasing of the vibration amplitude.