| In this research,the microstructure evolution process of ceramic tool materials is the research object.The purpose of the research is to improve the mechanical properties of ceramic tool materials.Based on the grain growth theory,the microstructure evolution process of pressureless sintering single-phase ceramic tool materials is simulated and analyzed by an improved Monte Carlo simulation algorithm.The microstructure evolution of ceramic tool material containing metal liquid phase and pores in pressureless sintering is simulated and analyzed by a further improved algorithm.The effect of ultrasonic cavitation on the grain growth of Ti B2 ceramic tool material containing metal Ni under pressureless sintering is studied on the basis of theoretical derivation and mathematical model.The microstructure evolution process of ultrasonic pressureless sintering Ti B2 ceramic tool materials containing metal Ni is simulated and analyzed by Monte Carlo method.The specific research contents and conclusions of this article are as follows:(1)Firstly,the grain growth theory of ceramic tool materials is analyzed and various factors affecting the grain growth of ceramic tool materials are clarified.The Monte Carlo simulation method for solid phase grain growth is improved.The improved Monte Carlo algorithm simplifies the process of reorienting lattice points and improves the simulation efficiency.Based on the improved algorithm,the program of Matlab software is used to simulate the microstructure evolution of single-phase ceramic tool materials.(2)In order to further analyzing the effects of metal phase and pores on the microstructure evolution of ceramic tool materials,the existing algorithm for dissolution and precipitation of solid phases in liquid phase is improved,then a Monte Carlo simulation model of the ceramic tool materials containing metal phase and pores is established based on improved single-phase ceramic tool material microstructure simulation algorithm.The effects of temperature,holding time,porosity and liquid phase on the growth of grains of solid phase are analyzed by modifying the simulation parameters and comparing the simulation results.(3)In order to reveal the effect of ultrasonic cavitation on the grain growth of ceramic tool materials,the occurrence conditions of ultrasonic cavitation under pressureless sintering environment are analyzed.An ideal model of bubbles and surrounding grains is established.It can be known from the calculation that ultrasonic cavitation can increase the particle vibration frequency and vibration energy,thereby increasing the lattice vibration frequency.The higher the frequency of lattice vibration is,the more easily the dendrites will break,and the broken dendrites will form new nuclei,which increases the nucleation rate and achieve the effect of refining the crystal grains.The effect of ultrasonic cavitation on the vibration frequency of particles is added to the Monte Carlo simulation method.The simulation results with and without ultrasound are compared under the same simulation conditions.It can be known from the simulation results that the final grain size under the application of ultrasound is smaller than that obtained when the ultrasound is not applied,and there are fewer large pores in the material.This shows that the application of ultrasound helps to refine the grains and reduce the size of pores,which can improve the mechanical properties of ceramic tool materials.The ultrasonic cavitation effect becomes more significant as the metal phase content decreases. |
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