Microstructure, properties and reaction kinetics of a Cu–Al2O3–TiB2 alloy prepared by a new liquid phase in-situ reaction technology

Cu–Al2O3–TiB2 is an important high-performance dual-phase dispersion strengthened copper alloy. The problem of serious coarseness and agglomeration of TiB2 and Al2O3 particles is a bottleneck that restricts the preparation of high-performance Cu–Al2O3–TiB2 alloys by traditional liquid-phase in-situ reaction method. In this paper, an idea of combining the split cavity melting of complex reactants and efficient solidification of melt was proposed, and a new liquid phase in-situ reaction technology for dual-phase strengthened metal matrix composites was invented. Compared with the traditional liquid phase in-situ reaction method, the strengthening particles in the Cu-0.75Al2O3-0.75TiB2 (wt.%, nominal composition) prepared by the new liquid phase in-situ reaction technology were more uniform, and the tensile strength and hardness were significantly improved. Large-deformation cold rolling can improve distribution of particles. With the increase of deformation, the main deformation mode of the composite changed from matrix plastic deformation to matrix-particle shear deformation, with the main fracture mechanism changing from particle-matrix interface fracture to particle shear fracture. The new liquid phase in-situ reaction technology effectively solved the problem of particle coarsening and agglomeration in Cu–Al2O3–TiB2 composites. The new liquid phase in-situ reaction technology combined with large deformation is a new process with high efficiency and short flow for preparing dual-phase dispersion strengthened copper alloys.