Properties Of Ceramic Tool Materials Research Articles

Design optimization of mechanical properties of ceramic tool material during turning of ultra-high-strength steel 300M with AHP and CRITIC method

Design optimization of mechanical properties is one of the most challenging tasks in the design and development of new tool materials for diverse machining applications. Mechanical properties of tool material play a crucial role during the entire tool design and machining process. This paper attempts to solve the optimization problem of mechanical properties for Al2O3-based ceramic tool material in turning of ultra-high-strength steel 300M. First, a high-speed turning experiment was conducted to explore the effect of various mechanical properties of ceramic tool materials on tool life, and then an exponential model was built to decompose the tool life for obtaining the best comprehensive mechanical properties of ceramic tools. Second, analytic hierarchy process (AHP) method combined with Criteria Importance Through Intercriteria Correlation (CRITIC) method was used to optimize the mechanical properties of ceramic tool materials. The optimization results of hardness, fracture toughness, flexural strength, and Young’s modulus were 21.3 GPa, 8.9 MPa·m1/2, 898.6 MPa, and 473.5 GPa, respectively. Finally, under the guidance of optimization results, Al2O3/TiC/TiN ceramic tool (AT10N20) materials were fabricated to turning of ultra-high-strength steel 300M. The cutting performance and wear mechanisms of ceramic tool AT10N20 were investigated. The experimental results indicated that the design optimization method could be useful for designing and developing new tool materials in specific machining applications.

Three-dimensional simulation of microstructure evolution for three-phase nano-composite ceramic tool materials

It is believed that adding particles can improve mechanical properties of ceramic tool materials. So far, two-phase composites materials have been widely investigated. However, materials with two-kinds of particles are seldom researched. In this paper, microstructure evolution of two-phase and three-phase nano-ceramic materials are simulated and compared. The effects of particle volume fraction, radius, distributions and grain boundary energy ratios on microstructure evolution are analyzed respectively. It shows that adding two kinds of particles can receive better grain refinement than just adding one kind of particles. The higher volume fraction and smaller-sized nano-particles have stronger pinning force on matrix grain growth. The nano-particles located around grain boundaries have better inhibition effect than those distributed randomly on matrix grain growth. Grain boundary energy ratio has significant influence on pinning effect of particles. The nano-particles not only restrain grain boundary migration, but also prevent the elimination of small grains and refine matrix grains.

Three dimensional simulation of microstructure evolution for ceramic tool materials

The observation and scientific quantitative characterization of three dimensional microstructure evolution during sintering process of ceramic tool materials is important to investigate the influence of nano-particles on mechanical properties. The relationship between microstructure and mechanical properties of ceramic tool materials can be established to direct the development of nano-composite ceramic tool materials by the research of the grain growth, grain boundary migration, distribution of nano-particles and microstructure densification at the different sintering temperature and pressure. In this paper, a 3D Monte Carlo model of three-phase nano-composite ceramic tool material is built and applied to simulate the microstructure evolution during sintering process. In this model, the grain boundary energy of each phase and interfacial energy between two phases are taken into consideration as the driving forces for grain growth. The sintering temperature and pressure are successfully coupled into the Monte Carlo simulation model. The microstructure evolution of defect free three-phase nano-composite ceramic tool materials is successfully simulated at different sintering temperature and pressure. The simulation results show that the higher the sintering temperature is, the faster the grain growth. However, the sintering pressure has little effect on the grain growth.

Simulation of Fabrication for Single-Phase Al<sub>2</sub>O<sub>3</sub> Ceramic Tool Materials at Different Fabrication Temperature

The fabrication is a key process for the preparation of ceramic tool materials, which governs the mechanical properties of ceramic tool materials under the condition of the same compositions. A computer simulation coupled with fabrication temperature for the hot-pressing process of single-phase ceramic tool materials has been developed using a two-dimensional hexagon lattice model mapped from the realistic microstructure without considering the presence of pores. The fabrication of single-phase Al2O3 is simulated. The mean grain size of simulated microstructure by Monte Carlo Potts model integrated with fabrication temperature increases with an increase in fabrication temperature, which is consistent with the experiment results.

Thermal shock behaviors of functionally graded ceramic tool materials

Abstract Thermal shock resistance of Al2O3–TiC and Al2O3–(W, Ti)C functionally graded ceramic tool materials with symmetrical structures were evaluated by water quenching and subsequent three-point bending tests of strength diminution. Comparisons were made with the results from parallel experiments conducted using homogeneous Al2O3–TiC and Al2O3–(W, Ti)C ceramic tool materials. Functionally graded cutting ceramics exhibited both increased critical temperature difference and increased strength retention properties compared to homogeneous cutting ceramics, indicating their higher thermal shock resistance. The experimental results were discussed and rationalized in terms of microstructural observations and the calculations of one-dimensional transient temperature fields and transient thermal stress fields in case of surface cooling by using the perturbation method. It was concluded that higher thermal shock resistance could be achieved by means of varying the compositional distribution and hence the resultant distribution of thermo-mechanical properties of ceramic tool materials appropriately.

Physical Properties of Ceramic Tool Materials : (Especially on the Adhesion of Ceramics)

This paper describes the adhesion of cutting tools at high temperatures from the results of empirical cutting data and fundamental test on the adhesion between cutting tool tips and work materials. The adhesive tests were run in vacuum except where noted by means of the Vickers hot hardness testing machine. In consequence, we found that the critical temperature for adhesion was affected by the chemical composition of ceramics and kinds of metals and that the strength of the interface between ceramic tips and metals was weaker than in the case of carbides and this fact was recognized as one of the reasons why the crater wear and built up edge in ceramics were less than in carbides.