X-ray microdiffraction studies to measure strain fields in a metal matrix composite

An x-ray diffraction microscope has been used to map the strain field in a fiber-reinforced composite material. The monochromatic x-ray (11 keV) beam was focused by a phase zone plate to produce a focal spot of 1 x 4 {micro}m{sup 2} on the specimen. The change in the peak position of diffraction patterns due to interatomic spacing change, caused by stress in the sample, was measured by using a two-dimensional CCD detector. The radial residual strain field in the fiber-reinforced composite (SCS-6/Ti-14Al-21Nb) was measured from diffraction patterns with a sensitivity of {approximately} 10{sup {minus}4} and an average standard deviation of 9.4 {times} 10{sup {minus}5}