The X-ray diffraction intensity of cyclically loaded Al

The displacement field around a dislocation loop had been calculated to give the diminishing factor of X-ray diffraction intensity from a fatigued Al sample. Experimentally had been measured this factor on the samples fatigued at room temperature and at low temperature. From these the size and density of dislocation loops can be deduced. Results show that in the sample fatigued at room temperature there is no significant change in dislocation structure while at low temperature in fatigued sample occurs a large amount of dislocation loops whose density is 10¹⁴?10¹⁷cm^?3 while their radii are between 100 and 1000 Å.