摘要
Dense B;C material was fabricated using spark plasma sintering(SPS), and the densification mechanisms and grain growth kinetics were revealed. The density, hardness, transverse flexure strength and toughness of samples were investigated and the model predictions were confirmed by SEM and TEM experimental observations. Results show that SPSed B;C exhibits two sintering periods: a densification period(1800-2000 °C) and a grain growth period(2100-2200 °C). Based on steady-state creep model, densification proceeds by grain boundary sliding and then dislocation-climb-controlled mechanism. Grain growth mechanism is controlled by grain boundary diffusion at 2100 °C,and then governed by volume or liquid-phase diffusion at 2200 °C.
通过放电等离子烧结(SPS)制备致密碳化硼材料,并揭示烧结致密化机制和晶粒生长动力学;研究样品致密度、硬度、抗弯强度和韧性,并通过SEM和TEM对烧结机制进行验证。结果表明,SPS碳化硼烧结主要分为两个阶段:致密化阶段(1800~2000℃)和晶粒生长阶段(2100~2200℃)。利用稳态蠕变模型进行分析,碳化硼烧结初期致密化机制为晶界滑移,后期转变为位错攀移机制;晶粒生长机制在2100℃时由晶界扩散控制,在2200℃时由体积扩散或液相扩散控制。
基金
the financial supports from the National Natural Science Foundation of China (No. 51874369)
Hunan Provincial Natural Science Foundation, China (No. 2021JJ30856)
the China Scholarship Council for financial supports (No. CSC201906370123)
the Fundamental Research Funds for the Central Universities of Central South University, China (No. 2020zzts084)。
