Microstructural, mechanical and tribological properties of ultrafine-grained Cu-Cr-Zr alloy processed by high pressure torsion

The effect of temperature on tribological properties of coarse grained (CG) and ultrafine-grained (UFG) Cu-Cr-Zr alloy processed via high pressure torsion (HPT) was investigated. Dominant wear mechanism depends on both temperature and microstructure of the alloy. Adhesive, abrasive and oxidative wear mechanisms are operative in all samples at room temperature. Adhesive wear mechanism is also operative at 200 degrees C. Oxidative wear is found to be another wear mechanism at that temperature. The breakdown of oxide layers generates spherical wear particles which activate another wear mechanism of three-body abrasive wear. Excessive oxide layer formation is observed at 400 degrees C. Thick oxide layer covers the worn surface and provides a wear-protective load-bearing layer which brings about high wear resistance at 400 degrees C especially for the CG samples. (C) 2019 Elsevier B.V. All rights reserved.