Measurement of residual stress on a unidirectional solidified Al2O3/YAG eutectic composite using synchrotron and neutron diffraction

The residual stress in the pure YAG phase was measured on the surface of an Al2O3-Y3Al5O12 (YAG) eutectic composite (Al2O3/YAG-MGC) using low energy synchrotron X-rays. The residual stress in the plane stress condition was significantly different between top and side surfaces of the specimen. In addition, the internal residual stress of the melt growth composite (MGC) was also measured using a neutron diffraction. The residual stress in the YAG phase rose from compression in the solidification direction to tension in the perpendicular direction. The residual stress in the Al2O3 phase was anisotropic compression and there was no tension in any direction. This anisotropic residual stress could be explained by the crystallographic anisotropy of thermal expansion in the Al2O3 phase. However, both phase stresses were not balanced, so that it is expected that there would be a stress distribution in the MGC.