Computer simulation of the temperature field in the hot pressing process of multi-phase composite ceramic material

摘要

Models of the heat transfer in the hot pressing process of ceramic materials have been built theoretically. Then, with the example of Al_2O_3/SiC/(W, Ti)C multi-phase composite ceramic material, designs of the hot pressing technology are made through the study of the temperature field in the ceramic blanks by means of computer simulation. It is shown that the heating and cooling rate and the existence of voids before sintering have great effects on the temperature field in the ceramic blanks. Under the experimental conditions, it is found suitable for the heating and cooling rates to be 0.5-0.75 and 0.33 deg C/s, respectively, through comprehensive consideration of the requirements of both the material properties 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 material will be improved further.