Enhancement of the wear resistance of CuAl9Fe4 sliding bearing bushings via diamond burnishing

Abstract

The effect of diamond burnishing (DB) on the wear resistance of two-phase CuAl9Fe4 bronze sliding bearing bushings was investigated experimentally via assessments of the surface integrity (SI) following different finishing processes, sliding wear tests and worn surface morphology analyses. The wear tests were performed under boundary lubrication and dry friction conditions. One- and six-pass DB increase wear resistance under boundary lubrication by 1.69 and 2.55 times, respectively, compared to the fine turning process. Under the dry friction condition, these increases amount to 2.27 and 2.15 times, respectively. Under boundary lubrication, the dominant wear mechanism is the micro-cutting inherent in abrasion; therefore, the geometric characteristics of surface integrity (SI) play a decisive role in mass wear. DB leads to a favourable combination of the 3D height and shape parameters for surface texture (ST), which improves lubrication and hence reduces friction and mass wear. Under dry friction, the dominant wear mechanism is adhesion for fine-turned specimens and abrasion for diamond burnished specimens. The physical-mechanical condition of the surface layer is dominant in terms of wear, and ST is of secondary importance for this friction regime. DB leads to significant improvements in the SI physical-mechanical characteristics.