K. Dzieciol

X-ray and neutron imaging – Complementary techniques for materials science and engineering

Abstract Using X-ray and neutron radiography and tomography, images of material and component inhomogeneities and their development with time can be obtained. Due to their non-destructiveness and non-invasive nature both methods give insight into the function of devices and their decay processes. Fundamentals of X-ray and neutron radiography and tomography are briefly outlined, examples for both techniques are given, their complementarities are highlighted and emerging techniques and frontiers are discussed.

Damage fluctuations in creep deformed copper studied with synchrotron X-ray microtomography

Abstract Damage localization during power law creep of copper has been investigated in situ with synchrotron X-ray microtomography. The analysis of the area fraction of cavities corresponding to a given material slice has revealed that damage localization begins relatively early at half of the creep lifetime. The amplitude of the maximum fluctuation shows parabolic behavior as a function of mean void volume fraction. Existing models of damage evolution underpredict the amount of real damage and overpredict power-law creep life-time.

Investigation of creep cavity coalescence in brass by in-situ synchrotron X-Ray microtomography

X-ray microtomography was applied for in-situ study of void coalescence during high-temperature creep of a brass alloy. Using image correlation techniques the movement of single slices and cavities connected to these images were monitored during deformation. Coalescence of voids was detected using ancestors analysis and independently checked with a geometrical parameter describing the distorted cavity shape. The analysis of in situ results suggests the existence of a critical volume fraction, as well as critical value of the ligament size between cavities at the onset of coalescence. The maximum number of primary coalescence events takes place in the tertiary stage of creep.