Effect of tool rotational speed on mechanical and tribological characteristics of friction stir processed CuNi/ZrC surface composites

Cupronickel (CuNi), an alloy of copper, has nickel as a major alloying element. However, meager wear resistance and tensile strength limited the application potential of CuNi alloys. This work applied friction stir processing to fabricate ZrC-reinforced CuNi surface composite to increase the mechanical and tribological properties. The influence of tool rotation speed (1100 rpm, 1300 rpm, and 1500 rpm) on the microstructural evolution, dispersion of reinforcement particles, microhardness, ultimate tensile strength, and wear behavior of the fabricated surface composite was investigated. Advanced characterization instruments such as field emission scanning electron microscope, energy dispersive x-ray spectroscope, and x-ray diffractometer were utilized to analyze the grain refinement, distribution of the reinforcement particles, fractography, and worn-out surface morphology. The results indicate that friction stir processing at a tool rotation speed of 1300 rpm would result in a higher average microhardness (206 HV), tensile strength (329 MPa), and an average lower wear rate (219 x 10-5 mm3/m).