A. Isaac

Study of cavity evolution during creep by synchrotron microtomography using a volume correlation method

Introduction Instrument development at third-generation synchrotrons over the last decade has enabled a large variety of in-situ experiments. Among these, X-ray microtomography represents a special case due to the three-dimensional (3D) character of the information acquired [1-3]. The method combines the high photon flux with the nondestructive nature of the investigation, enabling a deeper insight into the dynamics of physical processes. In-situ microtomography is very well suited for damage investigation during high-temperature creep, providing for the first time experimental 3D data about damage evolution. Such findings are of valuable help to understand the dynamics of the underlying physical processes and to promote further developments of adequate damage theories [4-6]. It is the aim of this report to present the qualitative features of cavity evolution during high-temperature creep of a brass alloy.

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.