Accession Number : AD0407069


Title :   THE ROLE OF THE GRAIN BOUNDARY IN THE DEFORMATION OF CERAMIC MATERIALS


Descriptive Note : Report for Jan 1962-Jan 1963


Corporate Author : MATERIALS RESEARCH CORP ORANGEBURG NY


Personal Author(s) : Murray, G T ; Mountvala, A J


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/407069.pdf


Report Date : Mar 1963


Pagination or Media Count : 33


Abstract : The mechanical behavior of MgO grain boundaries at elevated temperatures was investigated. The shear strength of bicrystal specimens was obtained (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 misorientations. For a given tilt angle the fracture stress decrease with 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 investigated for varying misorientations in the range 1200 - 1500 C. For each type of boundary orientation 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.


Descriptors :   *CERAMIC MATERIALS , *CREEP , EXPERIMENTAL DATA , DEFORMATION , GRAIN BOUNDARIES , MAGNESIUM OXIDES , TRANSITION TEMPERATURE , STRENGTH(MECHANICS) , FRACTURE(MECHANICS)


Subject Categories : Ceramics, Refractories and Glass


Distribution Statement : APPROVED FOR PUBLIC RELEASE