Microstructure and performance optimization of Al2O3/TiC/TiB2/h-BN@Al2O3 self-lubricating ceramic tool materials

Abstract

Based on the classical Monte Carlo (MC) model and grain growth theory, the model of h-BN@Al2O3 coated solid lubricant was designed and introduced into the simulation system. The Al2O3/TiB2/h-BN@Al2O3 self-lubricating composite ceramic tool model was designed, and the microstructure evolution of tool materials during hot pressing sintering was simulated. The effects of TiB2 and h-BN@Al2O3 content on the microstructure of ceramic materials were studied, and finally the optimized composition parameters were obtained. The effects of sintering temperature and sintering pressure on the microstructure of tool materials were studied, and reasonable sintering parameters were obtained. The experimental results show that under the sintering temperature of 1650℃ and sintering pressure of 32Mpa, the ceramic material with 10%volTiB2 and 5%volh-BN@Al2O3 has the best mechanical properties, that is, the bending strength is 610MPa, the hardness is 17.9GPa, and the fracture toughness is 5.17 MPa·m1/2. SEM analysis shows that the grain growth of the material is uniform, the solid lubricant is well combined with the matrix, and the material has a good microstructure. Comparing the simulation results with the previous experimental results, it is found that the results are in good agreement, which indicates that the designed MC model reliably reflects the physical process of material grain growth, and has certain guiding significance for further research on the mechanism of grain growth.