Nondestructive evaluation techniques for high-temperature ceramic components. Sixth quarterly report, January--March 1979

Technical Report · Sun Apr 01 04:00:00 EST 1979

DOI:https://doi.org/10.2172/6165222· OSTI ID:6165222

Tests comparing the effectiveness of radiographic and conventional ultrasonic techniques have shown that dye-enhanced neutron- and x-radiography techniques are capable of revealing surface flaws (in this case, small dents in a silicon nitride bar) which cannot be revealed by conventional radiographic or ultrasonic means. These results support the idea that dye-enhanced radiography may be useful for detection of flaws on surfaces not accessible for conventional dye-penetrant examination. A small (approx. 100 x 50-..mu..m) ''crack'' was made on the surface of a hot-pressed silicon carbide bar and various techniques were used in an attempt to detect it. Dye-penetrant, ultrasonic and radiographic techniques were not capable of detecting this flaw. Holographic-interferometry methods (with the bar stressed in a four-point bending fixture) were barely adequate to reveal the presence of the flaw. However, the Sonoscan acoustic microscope was able to detect the flaw unambiguously, via mode-converted surface waves scattered backwards from the flaw. Progress has been made in the development of a stage to be used with the acoustic microscope for demonstrating the feasibility of helically scanning SiC heat-exchanger tubing. Also, some apparatus has been acquired for demonstrating the adequacy of ultrasonic bore-side inspection of SiC tubing.

• Research Organization: Argonne National Lab., IL (USA)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 6165222
• Report Number(s): ANL/MSD-79-2
• Country of Publication: United States
• Language: English

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