Fabrication and damping capacity of CuZnAl matrix composites processed by powder metallurgy route

Abstract

Cu-26.5Zn-4Al (wt.%) alloy (as a matrix) and each of three different Fe-based ferromagnetic alloy flakes (as a reinforcing material) were processed into three different composites via conventional cold compaction; this was followed by hot isostatic pressing. The sliced sheets of the composites were heat-treated at 1073 K and quenched into ice water to introduce a martensitic structure. The damping capacity and the storage modulus were measured for three different composites as functions of strain amplitude and frequency. The microstructure of the composites was characterized by use of optical microscopy, scanning electron microscopy and scanning transmission electron microscopy in order to examine the martensite, the flake morphologies and the interfaces. In all three composites, the loss factor increased from 0.02 (with a strain of f100 × 10 −6) to approximately 0.05 (with a strain of 300 × 10 −6). In particular, the FeCr flakes/CuZnAl composites exhibited a maximum loss factor near a strain of 165 × 10 −6 , owing to the damping of the FeCr flakes.