Diamond composites with Al-Co binder: Synthesis, structure, wear resistance

•Composites are obtained by sintering of diamond powders with Co and Al at high pressures.•Diamond carcass and AlCo-AlCo3C binder provides a very high resistance.•Turninig of WC-Co hard alloy in a quasi-ductile mode is possible with this composites. Wear-resistant diamond composites without a tungsten carbide substrate were obtained by sintering mixtures of micron and submicron diamonds at 7–8 GPa, 1550–1700 °C. Cobalt and aluminum powders were used as sintering activators in a proportion that ensures the formation of microstructure with binding phases in the form of intermetallic AlCo and carbide AlCo3C. The influence of the morphology and sizes of diamond particles on the microstructure and performance characteristics of composites is considered. The possibility of hard alloy turning with new composites from homogeneous mixtures in the quasi-ductile mode is demonstrated. The wear resistance of experimental samples with optimized initial composition and shape of diamond particles significantly exceeds the characteristics of high-quality commercial composites used in drill bits.