The Role Of The Grain Boundary In The Deformation Of Ceramic Materials, Part II.
Report Number: ASD TDR 62-225 Part 2
Author(s): Murray, G. T., Mountvala, A. J.
Corporate Author(s): Materials Research Corporation
Laboratory: Directorate of Materials and Processes
Date of Publication: 1963-03
Pages: 32
Contract: AF 33(616)-7961
DoD Project: 7350
DoD Task: 735003
Identifier: AD0407069
Abstract:
The mechanical behavior of MgO grain boundaries at elevated temperatures was investigated. The shear strength of bicrystal specimens was ob tained (constant loading rate tests) at 1400 C for a wide range of crystal misorientations. Large twist, low tilt boundaries fractured at extremely low stress compared to other misorien tations. For a given tilt angle the fracture stress decrease th increasing twist component; the decrease being sharper for low tilt bound aries and more gradual for boundaries possessing large tilt components. The effect of temperature on the grain boundary fracture stress was inves tigated for varying misorientations in the range 1200 - 1500 C. For each type of boundary orien tation there was a characteristic temperature where there was a sudden drop in strength, this transition temperature being lowest for bound aries with a high twist component. Experiments on tricrystals indicated that the weaker twist type boundaries controlled the fracture strength of the entire body.
Provenance: Lockheed Martin Missiles & Fire Control
Author(s): Murray, G. T., Mountvala, A. J.
Corporate Author(s): Materials Research Corporation
Laboratory: Directorate of Materials and Processes
Date of Publication: 1963-03
Pages: 32
Contract: AF 33(616)-7961
DoD Project: 7350
DoD Task: 735003
Identifier: AD0407069
Abstract:
The mechanical behavior of MgO grain boundaries at elevated temperatures was investigated. The shear strength of bicrystal specimens was ob tained (constant loading rate tests) at 1400 C for a wide range of crystal misorientations. Large twist, low tilt boundaries fractured at extremely low stress compared to other misorien tations. For a given tilt angle the fracture stress decrease th increasing twist component; the decrease being sharper for low tilt bound aries and more gradual for boundaries possessing large tilt components. The effect of temperature on the grain boundary fracture stress was inves tigated for varying misorientations in the range 1200 - 1500 C. For each type of boundary orien tation there was a characteristic temperature where there was a sudden drop in strength, this transition temperature being lowest for bound aries with a high twist component. Experiments on tricrystals indicated that the weaker twist type boundaries controlled the fracture strength of the entire body.
Provenance: Lockheed Martin Missiles & Fire Control