Definitions, References & Data Sources
Simplified Definitions
Bend Strength: The maximum bending load (strictly speaking stress) that can be applied to the material before it breaks.
Compression Strength: The maximum compressive load (strictly speaking stress) that can be applied to the material before it crumbles.
Fracture Toughness: The toughness of a material, in simplest terms, can be described as the load (per unit area) required to initiate a crack when this load is applied to a surface. In this sense glass is not as tough as wood. A measure of the fracture toughness of a material is the Critical Stress Intensity Factor (K1c). It is calculated from crack lengths derived from the Vickers Hardness test and is a good approximation of the bend strength of a material. The usual bend strength test (e.g. SENB) is more elaborate and tedious to perform.
Hardness: The hardness of a material, in simplest terms, can be described as its ability to resist denting (or deformation), in the sense that stone is felt to be harder than wood when pressed. The Vickers Hardness (Hv) is one common measure of this property of a material. Other measures include the Knoop and the Rockwell Hardness.
Wear-resistance: The wear-resistance of a solid is broadly defined as the progressive removal of material from its surface under operational conditions. The abrasive wear-resistance of a material is related to its hardness, its fracture toughness and its elastic modulus (reference 9). Simply put, the harder the material, the more wear-resistant it is and the longer it would last under operational conditions.
References
(1) Lawrence H. Van Vlack "Elements of Materials Science and Engineering" Addison-Wesley Publishers, USA, 5th Edition (1985).
(2) K.Tsukuma and M.Shimada "Strength, fracture toughness and Vickers Hardness of CeO2-stabilized tetragonal ZrO2 polycrystals (CeTZP)" Journal of Materials Science; Volume 20, Pg 1178-1184 (1985).
(3) A.M.Hart, B.C.Peters, J.H.Plonka, W.H.Werst Jr and J.M.Macki "Advanced Ceramic Opportunities: A Review" Chemical Engineering Progress; Volume 85, Pg 32-52 (1989).
(4) M.M. Schwartz (Sikorsky Division, United Technologies Corp), "Ceramic Joining" ASM International Publishers, OH, USA (1990).
(5) S.J. Schneider (ed) "Ceramics and Glasses" in Engineered Materials Handbook, Volume 4, ASM International (1991).
(6) G.M.Carter, R.M.Hooper, J.L.Henshall & M-O. Guillou "Friction of Metal Sliders on Toughened Zirconia Ceramic between 298 and 973 K" Wear; Volume 148, pp 147-160 (1991).
(7) M.M. Schwartz "Handbook of Structural Ceramics" McGraw-Hill Publishers, USA (1992).
(8) James F. Shackelford "Introduction to Materials Science for Engineers" Macmillan Publishers, USA, 3rd Edition (1992).
(9) William A. Glaeser "Materials for Tribology", Series 20, Pg 4, Elsevier Press, NY and Amsterdam (1992).
(10) M-O. Guillou, J.L.Henshall, R.M.Hooper and G.M.Carter "Indentation Fracture Testing and Analysis, and its Application to Zirconia, Silicon Carbide and Silicon Nitride Ceramics" Journal of Hard Materials; Volume 3, Pg 421-434 (1992).
(11) William D. Callister Jr. "Materials Science and Engineering" John Wiley & Sons Publishers, USA, 3rd Edition (1994).
(12) E. Dow Whitney "Ceramic Cutting Tools" Pg 166, Chapter 7, Noyes Publications, USA (1994).
(13) M.H. Van de Voorde "Market Trends for Advanced Ceramics in Western Europe", American Ceramic Society Bulletin; Volume 75, Pg 47-50 (1996).
(14) E.A.Griffin, D.R.Mumm and D.B.Marshall "Rapid Prototyping of Functional Ceramic Composites" American Ceramic Society Bulletin; Volume 75, Pg 65-68 (1996).
(15) "Cambridge Materials Selector" A Materials Database - Version 2.04, Granta Design Ltd, UK (1997).
(16) Some values were obtained from the National Institute of Standards and Technology’s (NIST) WWW Version of the Structural Ceramics Database.
(17) Perry's Chemical Engineer's Handbook, McGraw-Hill, NY (1997).
(18) M.Matsuzawa, N.Yajima & S.Horibe "Damage accumulation caused by cyclic indentation in zirconia ceramics" Journal of Materials Science; Volume 34, Pg 5199 - 5204 (1999).
(19) http://www.ceramics.nist.gov/srd/summary/ftzrtzp.htm
(20) http://www.azom.com/default.asp