Tribological Characteristics of BrAMts9-2/W Composites Obtained by Means of Friction Stir Processing

Abstract

Microstructure, phase composition, as well as mechanical and tribological properties have been studied for composites based on a BrAMts9-2 bronze matrix reinforced with tungsten particles. Samples containing 0, 5, 10, and 15 vol % of W particles have been obtained by means of friction stir processing (FSP). It is shown that resulting from a multipass FSP of tungsten-containing samples, a composite structure is formed based on a multiphase bronze matrix consisting of α-Cu solid solution, intermetallic β′-Cu₃Al and γ₂-Al₄Cu₉ as well as uniformly distributed reinforcing tungsten particles. In the course of tribological testing, all the samples demonstrate similar values of friction coefficient ranging within 0.33–0.39. The wear rate of composites reinforced with the use of W are significantly lower than those of samples without W. The minimum wear rate values have been obtained for BrAMts9-2/5% of W samples. The tribo-oxidation effect in tungsten-containing samples is accompanied by the formation of the κ-phase of Al₂O₃ owing to the oxidation of the metastable γ-Al₄Cu₉ phase. The obtained composites can be use to fabricate moving parts of machines and devices, high-voltage electrical contacts, heat-removal elements, as well as for many other practical applications.