Paper Title:
Influences of Crack Face Bridging Stress and Microstructure on Fracture Toughness of Toughened Alumina Ceramics
  Abstract

Three types of polycrystalline alumina, one pressureless and two hot press sintered Al2O3, were used to examine the effects of the characteristics of microstructure and crack face bridging on fracture toughness. The crack opening displacements and microstructures along the pop-in crack of single edge precracked beam (SEPB) specimens were observed in situ at a constant applied stress intensity factor by scanning electron microscopy (SEM). The bridging stress distribution could be determined from the measured crack opening displacement by three-dimensional finite element analysis, and then the stress intensity factor and stress shielding effect at the crack tip could also be determined. Intergranular microcracks of toughened Al2O3 were deflected by a complicated microstructure, and crack closure due to bridging grains was observed near the crack tip. Bridging stress of Al2O3 was compressive perpendicular to the crack face and was distributed behind the crack tip. The maximum bridging stress of two hot press sintered Al2O3 was about twice as large as that of pressureless sintered Al2O3. The fracture toughness of hot press sintered Al2O3 was, therefore, higher than that of pressureless sintered Al2O3, because the total amount of bridging stress and stress shielding effect increased with increasing magnitude of microcrack deflection and the number of interlocking grains.

  Info
Periodical
Key Engineering Materials (Volumes 462-463)
Edited by
Ahmad Kamal Ariffin, Shahrum Abdullah, Aidy Ali, Andanastuti Muchtar, Mariyam Jameelah Ghazali and Zainuddin Sajuri
Pages
972-978
DOI
10.4028/www.scientific.net/KEM.462-463.972
Citation
Y. Sakaida, H. Yoshida, S. Mori, "Influences of Crack Face Bridging Stress and Microstructure on Fracture Toughness of Toughened Alumina Ceramics", Key Engineering Materials, Vols. 462-463, pp. 972-978, 2011
Online since
January 2011
Export
Price
$32.00
Share

In order to see related information, you need to Login.

In order to see related information, you need to Login.

Authors: Ji Sik Kim, Yong Nam Kwon, Kee Sun Sohn
Abstract:The present investigation aimed at visualizing the propagating crack in a mechano-luminescence (ML) material, which enabled us to measure...
1121
Authors: Ji Sik Kim, Kee Sun Sohn, Yong Nam Kwon, Gap Su Ban, Kwang Ho Lee
2264
Authors: Vladislav Kozák, Zdeněk Chlup
Abstract:Ceramic matrix composites reinforced by unidirectional long ceramic fibre are very perspective materials. The only disadvantage of such...
231
Authors: Vladislav Kozák, Zdeněk Chlup
Abstract:Silicon nitride based ceramics have received considerable attention during the last decades due to their very good room and high-temperature...
329
Authors: Vladislav Kozák, Zdeněk Chlup, Petr Padělek, Ivo Dlouhý
Chapter 3: Mathematical Modeling Microstructure, Deformation and Fracture
Abstract:Specific silicon nitride ceramics, the influence of the grain size and orientation on the bridging mechanisms was found. In ceramic matrix...
186