Researchers with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) have developed the first testing facility that enables CT-scanning of ceramic composites under controlled loads, at ultrahigh temperatures and in real-time.
The scientists created a mechanical testing rig for performing X-ray computed microtomography that reveals the growth of microcrack damage under loads at temperatures up to 1,750 degrees Celsius. The rig allows engineers to compute a ceramic composite material’s risk of structural or mechanical failure under extreme operating conditions, which in turn should enable the material’s performance and safety to be improved.
Berkeley Lab’s Advanced Light Source Beamline 8.3.2, which is powered by a 6 Tesla superconducting bend magnet, provides non-destructive 3D imaging of solid objects at a resolution of approximately one micron. With the addition of their unique tensile testing rig, the team maintains in situ ultrahigh temperature environments in either inert or oxidizing atmospheres while obtaining real-time 3D images of sample microstructures.
Exactly how micro-cracks are restrained by the tailored microstructures of a ceramic composite is the central question for the materials scientist seeking the optimal composition or architecture, and the design engineer who must predict the failure envelope, said Berkeley Lab materials scientist Robert Ritchie, adding that the only reliable way to answer this question is through measurements made at ultrahigh temperatures.
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