Densification mechanism during reactive hot pressing of B4C-ZrO2 mixtures |
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Authors: | Yan Xiong Xianwu Du Mingyu Xiang Hao Wang Weimin Wang Zhengyi Fu |
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Affiliation: | 1. Collaborative Innovation Center for Green Light-Weight Materials and Processing, Hubei Province Key Laboratory of Green Materials for Light Industry, Hubei University of Technology, Wuhan, 430068, PR China;2. Wuhan Branch of Baosteel Central Research Institute (R & D Center of Wuhan Iron & Steel Co., Ltd.), Wuhan, 430080, PR China;3. State Key Laboratory of Advanced Technology for Material Synthesis and Processing, Wuhan University of Technology, Wuhan, 430068, PR China |
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Abstract: | The densification behaviors of pure B4C and B4C-ZrO2 mixtures were compared during hot pressing. The results showed that in-situ formed ZrB2 effectively enhanced the densification process of B4C-ZrO2 mixtures, more significantly during the intermediate stage. Within the relative density ranging from 0.75 to 0.90, the B4C-15?wt%ZrO2 mixture (B15Z) achieved the maximum densification rate as twice much as that of pure B4C. The stress exponent n>3 indicated plastic deformation was the dominant densification mechanism of B15Z. The viscosities of plastic flow were evaluated using Murray-Rodger-William equation and the viscosity of B15Z was only a quarter of that in pure B4C. The sintering activation energy was calculated to be 305.9?kJ/mol for pure B4C and 197?kJ/mol for B15Z, respectively. It was proposed that the lower viscosity of plastic flow and activation energy accelerated the sliding and propagating motions of plastic flow, by which underlain the enhanced densification behaviors of B4C-ZrO2 mixtures. |
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Keywords: | Densification Sintering kinetics Plastic deformation |
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