Achieving well-balanced mechanical and tribological properties of copper matrix self-lubricating composites by adding pre-metallized B4C particles with core-shell microstructure

Copper matrix self-lubricating composites have the advantage of low friction coefficient, but usually suffer from the low mechanical strength , ductility and wear resistance. Ceramic particles reinforcing has been demonstrated an effective way in strengthening metal matrix composites . However, the poor wettability was always a critical issue. In this study, B 4 C particles were introduced into a copper matrix self-lubricating composite. Before spark plasma sintering , the B 4 C particles were pre-metallized with Ni to form a core-shell microstructure (Ni@B 4 C), which improves wettability and bonding strength with the copper alloy , builds up a coherent/semi-coherent interface, and notably enhances mechanical properties. After the incorporation of pre-metallized Ni@B 4 C particles, the compressive strength , hardness and engineering strain are increased by 62, 113 and 76%, respectively. What is more, the composite exhibits improved tribological performances . Owing to the successful transfer of lubricant WS 2 to the wear surface during sliding as well as the greatly enhanced hardness, its friction coefficient is decreased to 0.16, while the wear rate is reduced to 7.53 × 10 −6  mm 3 /N·m, which is 81% lower than that of CW . The composite achieves well-balanced mechanical and tribological properties after pre-metallized B 4 C particles incorporation.