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Abstract:The potential of the enhancement of superhard cutting tool performance on the basis of microstructural modifications of the tool materials is studied. Hybrid machining tools with mixed diamond and cBN grains, and machining tools with composite nanomodified metallic binders are developed, and tested experimentally and numerically. It is demonstrated that both combinations of diamond and cBN (hybrid structure) and nanomodification of the metallic binder (with hexagonal boron nitride/hBN platelets) lead to sufficient improvement in the machining performance. Superhard tools with 25% of the diamond replaced by cBN grains demonstrate 20% increased performance as compared with pure diamond machining tools, and more than two times higher performance compared with pure cBN tools. Furthermore, the machining efficiency of the wheels modified by hBN particles was 80 % more efficient compared with the tools with the original binder. A computational model of hybrid superhard tools is developed, and applied to the analysis of the structure-performance relationships of the tools.Keywords: Composites; Nanoreinforcement; Machining tool IntroductionThe productivity of cutting tools from superhard materials (SHM) determines the quality and costs of manufacturing many industrial products. The performance of machining tools depends to a large degree on the microstructural parameters of the tools, e.g., binder properties, cutting grain distribution and strength, and grain/binder bonding [1][2][3][4][5][6].The problem of the enhancement of material properties by tailoring material structures is one of the most important challenges of materials science [7]. Still, the microstructural improvement of machining tools, including nanostructuring and hybridization, is a relatively new subject.In this paper, we seek to explore the potential effects of hybrid and nanomodified structures of Hybrid diamond/cBN cutting tools: Optimization of composition and structuresDiamond monocrystals are typical abrasive elements of segmental cut-off wheels for concrete cutting. Their advantages over other SHMs include their high hardness as well as static and dynamic strength. Because cutting using cut-off wheel tools is performed at 1500-3000 revolutions per minute (rpm), the ability of SHM grains to stay intact under constant 3 mechanical loads is essential. The resistance of SHMs to chemical wear is also critical for cutting steel or cast iron. This wear results from diamond graphitization followed by carbon diffusion to the material being treated. To develop high quality cutting tools for steels and cast irons, two problems need to be addressed: 1 -to increase the hardness, strength and impact resistance of a binder and ensure its ability to securely retain the SHM grain [23][24][25]; 2 -to ensure the undamaged condition and integrity of SHM grains for the low wear of the binder.While using diamond to manufacture rope saws and segmental cut-off wheels for cutting steel and cast iron is undesirable due to the chemical wear caused by diamond grap...

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