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Refractories and Industrial Ceramics

, Volume 39, Issue 3–4, pp 80–85 | Cite as

The problem of thermal stability of ceramic materials

  • D. A. Ivanov
  • A. S. Balabanov
  • G. A. Fomina
  • N. A. Alad'ev
  • G. E. Val'yano
Research
  • 68 Downloads

Abstract

The thermal stability of ceramic materials is considered from the standpoint of fracture mechanics as a property determined by the capacity of the structure to resist the appearance and propagation of cracks on critical defects under the effect of thermal stresses. A method is suggested for comparative evaluation of the thermal stability of ceramics according to which specimens with a notch simulating a structural defect responsible for fracture are subjected to thermal shock. The absence of induced defects in the region adjoining the tip of the notch is a necessary condition for providing reproducible results. The resistance to thermal shock is determined from the relative decrease in the crack resistance after the thermal shock, the “insensitivity” of the structure to defects, and the degree of their accumulation in the region of the tip of the notch as a result of the thermal shock. The first and second criteria for evaluation of thermal stability involve the coefficient of relaxation of thermal stresses and the ultimate bending strength of the notched specimen. A ceramics of ZrO2 partially stabilized by 3 and 12% Y2O3 and a cermet with a composition of ZrO2-3 vol.% Y2O3-50 vol.% Cr are chosen for studying thermal stability by the method developed. Calculated results on the thermal stability of the cermet are compared with results obtained directly by thermocycling with variation of the metal content from 10 to 50%. The maximum mechanical properties are shown to correspond to a metal content of 40% due to formation of double-skeleton structure in the cermet. The method can be helpful for evaluating the initial stage of fracture caused by a thermal shock in structural ceramics.

Keywords

Thermal Stability Thermal Stress Ceramic Material Thermal Shock Crack Resistance 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Plenum Publishing Corporation 1998

Authors and Affiliations

  • D. A. Ivanov
    • 1
  • A. S. Balabanov
    • 1
  • G. A. Fomina
    • 1
  • N. A. Alad'ev
    • 2
  • G. E. Val'yano
    • 3
  1. 1.K. É. Tsiolkovskii Moscow Aircraft Engineering InstituteRussian State Engineering UniversityMoscowRussia
  2. 2.Institute for Problems of Data Communication of the Russian Academy of SciencesMoscowRussia
  3. 3.Research Center of the Joint Institute of High Temperatures of the Russian Academy of SciencesMoscowRussia

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