Interrelation Analyses of Mechanical Properties in Commercial Ceramics Using Cataloged Data

Abstract

Under conditions specified in this work, mechanical properties of commercial alumina, silicon carbide, silicon nitride and zirconia ceramics were selected from published manufacturers' catalogs. Numerical data of the selected properties for materials of 254 kinds in total were finally compiled in a computer-readable database. Interrelations among these properties were analyzed by using the database, and analyzed results were discussed. The selected properties of Young's modulus, linear thermal expansion coefficient, bending strength, Vickers hardness and fracture toughness were correlated with an apparent porosity derived from the theoretical and bulk density. Relationships of the selected properties to the porosity were fitted to exponential functions, and a good fitness was confirmed in most of the cases with a few exceptions. In general, every mechanical property tended to decrease with increasing the porosity. Although the hardness variation with respect to the bending strength was expressed by a proportional relationship for alumina and silicon carbide, a power relation was more adequate for silicon nitride and zirconia. The relation between the fracture toughness and the bending strength was fitted to a power function. In this case, a good fitness was identified for silicon carbide and zirconia, though a poor correlation was found for alumina and silicon carbide. A specific crack length, which was used to modify a fracture mechanics criterion for small cracks, was well correlated with the bending strength by a power function.

Effects of porosity and pore distribution on static strength properties of porous zirconia

“…As enlisted in the Handbook of Fine Ceramics Technology, 24,25 the fracture toughness for partially stabilized zirconia is 3.6 MPa m 1/2 . This value is taken as reference for the fracture toughness of nonporous zirconia in this study.…”

A statistical approach to strength evaluation incorporating porosity effect for porous ceramics

“…where a , b and c are material constants. Although the formulation as is sometimes applied to express the dependence of strength on porosity, 1,19 , 20 is a simpler function compared with and also easier in its practical application. Consequently, is adopted in the following analysis.…”

“…Although the formulation as Eq. (15) is sometimes applied to express the dependence of strength on porosity, 1, 19,20 Eq. (14) is a simpler function compared with Eq.…”

Estimated and Evaluated Residual Stress by Vickers Indentation in Several Structural Ceramics

“…Fracture toughness in ceramics is strongly influenced by the presence of residual stress as measured by the indentation method [5,[8][9][10]. If the apparent fracture toughness of ceramics with residual stress is set to KCA, and the fracture toughness of materials without residual stress is set to KC (the baseline fracture toughness), the relationship between them can be represented by the following Eq.…”

“…Thus, it is important to measure residual stress when designing and using ceramic products. Although the X-ray diffraction method is usually used for this purpose, the indentation method (Indentation Fracture (IF) method) is also used for its simplicity and speed [1,[4][5][6][7][8][9]. Recently, this method was prescribed as a standard by the Society of Materials Science, Japan (JSMS-SD-4-01) [4].…”