A wear-resistant Al85Cu6Fe3Cr6 spray-formed quasicrystalline composite

Abstract

An Al-based quasicrystalline composite has been processed by spray-forming resulting in a microstructure containing α-Al and a decagonal quasicrystalline phases as the major constituents. Microstructural characterization was performed by scanning and transmission electron microscopy, including detailed analyses of single quasicrystalline particles. In addition, the unlubricated sliding wear behavior of the composite was studied by pin-on-disk tests using several testing parameters, with normal loads ranging from 5 to 20 N and sliding wear velocities ranging from 0.05 to 0.2 m/s. For comparison basis, an Al-Si A380 commercial alloy was tested under the same wear parameters. The quasicrystalline composite showed a significantly higher wear resistance when tested with normal loads in the range of 5 to 10 N, with wear rates ranging from 4 to 6 × 10−4 mm3/N.m against 1 to 2 × 10−3 mm3/N.m for the Al-Si alloy. When tested under higher normal loads, 20 N, both materials presented similar values of wear rates. For lower normal loads, the worn surfaces of the composite and the Al-Si alloy showed that delamination wear was the main mechanism of material removal. However, with load increase, a higher fraction of hard intermetallic particles, previously removed by delamination, introduced a strong abrasive component into the wear track, which led to higher wear rates.