多相复合陶瓷刀具材料热压过程的计算机模拟与工艺设计Ⅰ——温度场模拟与工艺设计

Computer Simulation of the Hot Pressing Process in Multi-phase Composite Ceramic Tool Material and the Technological Design Ⅰ——Simulation of the Temperature Field and the Technologial Design

建立了陶瓷刀具材料热压过程的传热模型 ,并以 Al2 O3/ Si C/ (W,Ti) C多相复合陶瓷刀具材料为例 ,通过采用计算机模拟技术对坯体温度场的研究 ,进行了相应的热压工艺设计 .结果表明 :升降温速率的大小及烧结前气孔的存在对坯体内温度场影响较大 .综合考虑材料性能和制备效率的要求 ,在本试验条件下 ,升温速率以 0 .5～ 0 .75℃ / s而降温速率以 0 .3 3℃ / s为宜 .从温度场的角度来看 ,在陶瓷刀具材料热压成型之前 ,应先冷压成坯 ,以提高坯体的初始相对密度 ,降低热压过程中的温差 。

Models of the heat transmission in the hot pressing process of ceramic tool material have been built theoretically. Then, with the example of Al 2O 3/SiC/(W,Ti)C ceramic tool material, designs of the hot pressing technology are made through the study of the temperature field in ceramic blanks by means of the computer simulation. Results show that the temperature increasing and decreasing rates and the existing of the voids before sintering have a great effect on the temperature field in ceramic blanks. Under the experimental conditions, it is suitable for the rates of temperature increasing and decreasing to be 0.5～ 0.75℃/s and 0.33℃/s, respectively through the comprehensive consideration of the need of both the material property and the manufacturing efficiency. From the view of the temperature field, the ceramic blanks should be cold-pressed first before hot pressing. Thus, the initial relative density of the blanks can be increased and the temperature difference can be reduced. As a result, the physical and mechanical properties of the ceramic tool material will be improved.