Wear Characterization of Al/Ingredients MMFC

Abstract

In this study, dry sliding wear behavior of Al alloy (Al 2219) based metal matrix friction composites (AlMMFCs) incorporated with varying percentage of ingredients: silicon carbide particles (15–25 wt %SiCp) and solid lubricants with 4 wt % graphite and 1 wt % antimony trisulphide (Sb2S3) were investigated. A group of four new chemical formulations, three binary composites of Al/SiCp (Al01N, Al02N, and Al03N), and a hybrid composite of Al/SiCp/solid lubricants (Al04N) were fabricated by newly a developed “cold-hot powder die compaction” method. Physical and mechanical properties were measured as usual. To measure tribological properties, dry pin-on-disk wear tests were conducted for 1 hour at varying loads of 1 MPa and 2 MPa and at sliding speeds of 3 m/s, 5 m/s, 7 m/s, and 9 m/s. The results revealed that the incorporation of SiCp from 15 wt % to 25 wt % in binary composite, density (2.8–2.9 g/cc), apparent porosity (1.4–3.4 vol %), and hardness (78–93 BHN) were increased. For hybrid composite, density (2.9–2.76 g/cc) and hardness (93–81 BHN) were decreased with the increase in apparent porosity (3.4–4.1 vol %). It was concluded that the obtained density is higher than the reported density and the obtained apparent porosity is much lower than the reported apparent porosity by Aigbodi et al. (2007, “Effects of Silicon Carbide Reinforcement on Microstructure and Properties of Cast Al–Si–Fe/Sic Particulate Composites,” Mater. Sci. Eng., A, 447, pp. 355–360) for same composition using “double stir casting” method. The value of coefficient of friction with addition of solid lubricants increased and steady at high load and speed (2 MPa, >5 m/s).The microstructures, worn surfaces, and tribolayers are also analyzed by an optical microscope and SEM. This study overviews AlMMFCs incorporated with hard particles and solid lubricants and the new technology for producing brake lining parts from these novel materials.