Effect of temperature on the fracture of sapphire

Abstract At low temperatures, metastable crack growth dictates the environment free strength of sapphire. Plastic deformation by dislocation motion or twin formation and growth plays no role in the fracture process at temperatures below 400° C. These conclusions are supported both by crack growth studies and critical stress intensity factor measurements on sapphire crystals, and by transmission electron microscopy studies of arrested cracks in sapphire and alumina.

[1]  P. Gibbs,et al.  Fracture of Ge and Al2O3 , 1963 .

[2]  B. Hockey.  Plastic Deformation of Aluminum Oxide by Indentation and Abrasion , 1971 .

[3]  G. Hochstrasser,et al.  Surface states of pristine silica surfaces: I. ESR studies of Es′ dangling bonds and of CO2− adsorbed radicals , 1972 .

[4]  Elizabeth A. Jackman,et al.  The strength of single crystal and polycrystalline corundum , 1955 .

[5]  R. Dutton,et al.  The propagation of Griffith cracks at high temperatures by mass transport processes , 1971 .

[6]  S. Wiederhorn.  Fracture of Sapphire , 1969 .

[7]  R. Thomson,et al.  Lattice theory of fracture and crack creep , 1973 .

[8]  J. B. Wachtman,et al.  Plastic Deformation of Ceramic‐Oxide Single Crystals, II , 1954 .

[9]  J. Congleton,et al.  The brittle fracture of alumina below 1000°C , 1969 .

[10]  Harold Liebowitz,et al.  Fracture of metals , 1969 .

[11]  Sheldon M. Wiederhorn,et al.  Critical Analysis of the Theory of the Double Cantilever Method of Measuring Fracture‐Surface Energies , 1968 .

[12]  A. A. Griffith.  The Phenomena of Rupture and Flow in Solids , 1921 .

[13]  S. Wiederhorn,et al.  Crack Healing in Glass , 1970 .

[14]  J. Burke,et al.  Ultrafine-Grain ceramics , 1970 .

[15]  Dependence of Ultimate Strength of Glass Under Constant Load on Temperature, Ambient Atmosphere, and Time , 1953 .

[16]  J. W. Obreimoff.  The splitting strength of mica , 1930 .

[17]  R. Coble,et al.  Spheroidization of Tubular Voids in Al2 O3 Crystals at High Temperatures , 1972 .

[18]  J. P. Berry.  Some kinetic considerations of the Griffith criterion for fracture—I: Equations of motion at constant force , 1960 .

[19]  J. B. Wachtman,et al.  Strength of Synthetic Single Crystal Sapphire and Ruby as a Function of Temperature and Orientation , 1959 .

[20]  H. W. Liu.  Stress-Corrosion Cracking and the Interaction Between Crack-Tip Stress Field and Solute Atoms , 1970 .

[21]  J. Congleton,et al.  Dislocation movement in the brittle fracture of alumina , 1966 .

[22]  K. Sun,et al.  FUNDAMENTAL CONDITION OF GLASS FORMATION , 1947 .