FATIGUE STUDIES IN ENGINEERING MATERIALS BY DIFFRACTION OF PENETRATING RADIATION

摘要

In the past decade the technique of diffraction of penetrating radiation, that once was the reserve of the physicists, chemists and biologists, has developed into a novel versatile experimental method available to the materials scientist and mechanical engineer. The present paper illustrates the use of two configurations, the time-of-flight neutron spectrometry and high-energy synchrotron X-ray diffractometry, in situations relevant to fatigue and fracture. TOF neutron diffraction was used to monitor the grain level interactions during low-cycle fatigue of AISI 316L austenitic stainless steel in order to assess the crack initiation in the grains of a particular orientation. High-energy synchrotron X-ray diffraction was used to map the strains in the vicinity of a crack in an aluminium alloy. It is shown that the ability of the method to provide spatially and time resolved quantitative information about the bulk strains and stresses makes it a valuable tool for the structural engineer.