Development of functionally graded Cu–Sn–Ni/Al₂O₃ composite for bearing applications and investigation of its mechanical and wear behavior

ABSTRACT

This study investigates the mechanical and tribological properties of a functionally graded Cu–Sn–Ni/Al₂O₃ metal matrix composite, synthesized using horizontal centrifugal casting technique with dimension Φ_out100 × Φ_in85 × 100 mm. The microstructure was examined along radial distances at 1, 8, and 13 mm from outer periphery. Specimens were tested for tensile strength from outer (1–8 mm) and inner zone (9–15 mm) of the casting and fractured surfaces were subjected to fractographic analysis. Wear resistance of inner layer was experimented using pin-on-disc tribometer based on Taguchi’s L₂₇ orthogonal array using three variable process parameters, such as applied loads (10, 20, and 30 N), sliding velocities (1, 2, and 3 m/s), and distances (500, 1000, and 1500 m). Optimum parameters were determined for wear rate on “smaller-the-better” basis using signal-to-noise ratio. Analysis of variance predicted the effect of each influential parameter and their interactions. Results depict that wear rate increased with load and distance, forming phases such as Cu₃Sn, Ni₃Sn, Cu₆Sn₅, etc. Worn surfaces analysis using scanning electron microscope predicted the formation of mechanically mixed layers, showing a V-trend influence of velocity on wear. Thus, fabricated composite shows the replaceability of conventional leaded bearing materials with superior copper functionally graded composites having better wear characteristics.

KEYWORDS:

• Adhesive wear
• analysis of variance
• centrifugal casting
• functionally graded materials
• scanning electron microscope
• signal-to-noise ratio
• Taguchi

Additional information

Funding

This work was supported by the Defence Research and Development Organisation [Grant Number ERIP/ER/1503188/M/01/1587].