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Residual strength of porous alumina ceramics and fractal characterization of their crack patterns after thermal shocks.

Authors :
Shuai, Yaping
Ai, Jianping
Hu, Liling
Xu, Hongcheng
Cheng, Lihong
Chen, Zhiqin
Zhou, Zehua
Li, Wenkui
Source :
Ceramics International. Nov2024:Part A, Vol. 50 Issue 21, p41848-41856. 9p.
Publication Year :
2024

Abstract

Thermal shock behaviors of porous alumina samples with different porosities (4.6–16.0 %) and mean grain sizes (2.72–5.02 μm) were investigated under different quenching temperatures. The slit island method was used to analyze the structures of the pores. The effect of the pore structure on the thermal shock resistance of alumina ceramics was described quantitatively. The results revealed that the thermal shock resistance decreased when the fractal dimension of the pores increased. Alumina ceramic strips with a porosity and mean grain size of 4.6 % and 5.02 μm, respectively, were fabricated using raw powders with a mean particle size of ∼0.3 μm. These samples possessed the highest residual strength ratio (∼46.16 % at 600 °C) and critical temperature difference (∼262 °C). In addition, the fractal characterization of cracks on the surfaces of the alumina ceramics after thermal shock was carried out using the box-counting dimension method. In addition, we investigated the correlation between the mechanical properties and fractal dimensions of the surface cracks. The box-counting dimension increased with crack propagation and negatively correlated with the residual strength. Furthermore, the propagation rate of the surface cracks decreased as the temperature difference increased, resulting in a decrease in the growth rate of the fractal dimension. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
02728842
Volume :
50
Issue :
21
Database :
Academic Search Index
Journal :
Ceramics International
Publication Type :
Academic Journal
Accession number :
179952890
Full Text :
https://doi.org/10.1016/j.ceramint.2024.08.038