Thermal Wave Effect and Sintering Activation Energy at the Initial Stage of Field Assisted Sintering Process for Non-conductive Al_2O_3 Powders

作     者：ZHANG Long 张龙;ZHANG Xiaomin;ZHENG Hengwei

作者机构：Department of Theoretical and Applied Mechanics Chongqing University of Science and Technology Department of Engineering Mechanics Chongqing University 

出 版 物：《Journal of Wuhan University of Technology(Materials Science)》 (武汉理工大学学报（材料科学英文版）)

年 卷 期：2018年第33卷第6期

页      面：1416-1421页

核心收录：

学科分类：08[工学] 

基　　金：Funded by the National Natural Science Foundation of China(No.11602042) the Chongqing Research Program of Basic Research and Frontier Technology(No.cstc2016jcyjA0259) the Scientific and Technological Research Program of Chongqing Municipal Education Commission(No.KJ1601304) 

主　　题：field assisted sintering technique generalized thermoelastic theory thermal wave vacancy concentration difference sintering activation energy 

摘      要：The effect of thermal wave at the initial stage for non-conductive Al_2 O_3 powders compact in field assisted sintering technique(FAST) was investigated. The Lord and Shulman type generalized thermoselastic theory was introduced to describe the influence of thermal-mechanical interaction, as well as the heat transport and thermal focusing caused by thermal wave propagation. The expression of vacancy concentration difference of the particles was deduced by considering transient thermal stress. Subsequently, the relationship between activation energy and vacancy concentration difference was obtained. The mechanism of surface diffusion, volume diffusion, simultaneous surface and volume diffusion was analyzed. The numerical simulations indicate that low sintering temperature can obtain high local temperature by the superposition effect of thermal wave. Vacancy concentration differences were improved during FAST compared with hot-pressure and pressureless sintering, thereby decreasing the sintering time. By contrast, the activation energy declined with the decrease of vacancy concentration difference in the neck growth process.