Processing and failure studies of advanced composites using x-ray tomographic microscopy (XTM)

摘要

The traditional role of Non-Destructive Testing (NDT) has been to identify critical flaws in components after they have been fabricated. Recently, efforts have been made to introduce NDT techniques earlier in the engineering cycle, and some progress has been made in applying NDT inspection during component processing. Improvements that have been made in the spatial resolution and sensitivity of x-ray computed tomography (CT), however, indicate that it is now possible to introduce NDT concepts and methods to the earliest stage of component manufacture, namely, in the development of new materials -- where the characterization and analysis of microscopic features are important. X-ray tomographic microscopy (XTM) is a high resolution, three-dimensional variant of CT with a spatial resolution better than 0.005 mm. These studies have demonstrated that XTM is a powerful NDT technique which is capable of imaging microstructural features in even the most complicated advanced composite materials. Work is in progress to use XTM for dynamic studies of chemical vapor infiltration in continuous fiber ceramic composites. Furthermore, an in-situ tensile load frame is now being used in conjunction with XTM to study fatigue crack growth and tensile failure in metal matrix composites. The application of NDT imaging methods to materials studies will greatly enhance our understanding of time-dependent behavior in complex engineering materials. 3 refs.