Prediction of Strength of Graphitic Material by Nondestructive Test Techniques
SourceA material consisting of zirconium diboride, zirconium carbide, and silicon carbide dispersed in a continuous graphite matrix was examined by nondestructive test techniques. To improve reliability of the material, a method of predicting strength was desired. Testing consisted of bulk density, penetrant, X-ray, eddy current, and ultrasonic measurements. These were correlated with compressive and flexural strength measurements. Penetrant, X-ray, and ultrasonic measurements, as performed, did not provide any useful information for the prediction of strength. Bulk density and eddy current measurements correlated with strength. Since density (and strength) were found to vary significantly over very short distances within the material, density alone did not provide sufficient information to predict strength. However, by the use of a combination of density to determine an average strength, and eddy current readings to measure local variations in strength, it was found that the strength of a graphite part could be predicted.