初始晶粒尺寸为0.33μm和7.0μm的Al2O3/14%B4C粉末在不同温度烧结,并模拟计算陶瓷粉末烧结过程。通过对比实验结果和计算结果,找出影响材料致密化的机制,讨论晶粒尺寸对扩散机制的影响,并估算出致密化激活能。在实验烧结温度范围内,界面反应被认为是影响Al2O3/B4C粉末致密化过程的主要因素。Al2O3/14%B4C陶瓷的致密化激活能是1820±60KJ.mol-1,这结果很大程度上支持界面反应致密化机制。
Al2O3/14%B4C powders with the initial grain sizes of 0.35μm and 7.0μm,respectively,were sintered at different temperatures.Constitutive laws for densification were employed to model the sintering process of Al2O3/B4C ceramics.Based on the constitutive laws employed and the experimental results obtained,the dominant densification mechanism was identified and the effect of grain size on dominant densification mechanism was discussed.The activation energy for densification was also evaluated.In the investigated sintering temperature range,interface reaction was identified as the controlling process in sintering of Al2O3/B4C powders.The activation energy for densification of the Al2O3/14%B4C ceramics was determined as 1820±60KJ.mol-1,which provided a strong support on the densification mechanism.
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