Investigations on microstructure, wear behavior and corrosion resistance of brass/graphite composite produced by friction stir processing

In this study, a brass alloy-based (Cu-30%Zn) composite was fabricated by Graphite particles with initial size of 7µm reinforcement via friction stir processing. Groove with the Width and depth of 0.3mm & 2.5 mm were made on the surface of a brass specimen, respectively and filled by Graphite powder. Friction stir processing was carried out with transverse and rotational speeds of 100mm/min and 800rpm, respectively and the tilt angle of 1°. Single pass and three-pass FSP were conducted on the samples. The microstructure and mechanical properties before and after FSP were investigated. Optical and scanning electron microscope observations revealed that increasing the number of passes exhibits homogeneous distribution of Graphite particles. The wear behavior was examined without lubricant and at room temperature using a pin-on-disc device. The results showed that the wear resistance of composite layers containing MoS2 particles has increased to about 1.5 times the substrate. Maximum hardness in the stir zone was 141 Vickers, while the hardness of base metal was 84 Vickers. TOEFL test results also showed that the corrosion potential layer composite with graphite particles near to the values of the base metal had no significant change. While the corrosion potential in the processed layer without reinforcing particles of the base metal is approximately 48 Mv.