アルミナ長繊維強化アルミニウム複合材料における熱残留応力のX線3軸解析(X線材料強度小特集)

概要

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The stress due to the difference in coefficient of thermal expansion between matrix and fiber was measured by the X-ray diffraction method. The triaxial state of the matrix thermal residual stress in a 17μm diameter Al_2O_3 fiber/Al matrix composite was determined. In the matrix of the annealed composite a tensile residual stress state was observed. On the measurement after cooling the annealed composite to liquid nitrogen temperature, the matrix showed a compressive stress state in the composite. In both of the matrix stress states, the longitudinal residual stress parallel to the fibers was the maximum principal stress and the transverse residual stress normal to the fibers was about 40% of the longitudinal residual stress in magnitude. The stress normal to the surface was found to be about a half of the transverse stress. This can be due to the relaxation of the component of residual stress in the matrix near the surface layer. The X-ray in-situ measurements were made on the heating process of the annealed composite from 290K to 350K. The matrix tensile residual stress at 290K decreased linearly with increasing measurement temperature. The experimental results agreed well with the prediction based on a simple elastic concentric cylinder model.
1994-07-15