Microstructure and mechanical properties of microwave-sintered Ni-alloyed Ti3SiC2/graphene co-reinforced lamellar porous Fe-7.5Cu composites

Abstract

Porous Fe–Cu alloys are crucial for frictional applications such as bearings and gears, where their low density and porosity are advantageous for lubrication. However, the inherent microstructural defects hinder the achievement of high strength and ductility under harsh conditions, limiting their durability and widespread application. This study aims to address this deficiency through the synergistic optimization of Ni alloying and dual-phase reinforcements within biomimetic layered structures. The method combines microwave sintering with flake powder metallurgy technology, incorporating 1–7 % Ni into the Fe–7.5Cu matrix, while adding 1 % copper-coated graphene (GNP(Cu)) and 6 % Ti₃SiC₂ to enhance the control effects. The composite material with 7 % Ni demonstrates excellent performance: a tensile strength increase of 25.13 %, reaching 232.3 MPa, and a compressive strength increase of 16.14 %, reaching 675.1 MPa, with an average copper particle size increase of 79.46 % due to the sintering effects promoted by Ni. These improvements arise from the solid-solution effect and grain refinement induced by nickel, complemented by the Orowan effect, thermal mismatch, and load transfer mechanisms from GNP(Cu), Ti₃SiC₂, and TiC/Fe₃C products, which together suppress dislocations and refine the microstructure while maintaining approximately 23 % porosity. The advantage of this approach lies in achieving a balanced synergy between strength and ductility, avoiding excessive densification, and providing new insights into the alloying strategies for high-performance sustainable porous metal matrix composites in harsh industrial environments.