The Need for Experimentally Determined X-Ray Elastic Constants
NORTHWESTERN UNIV EVANSTON IL DEPT OF MATERIALS SCIENCE
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In order to convert residual strains measured by X-ray diffraction techniques into residual stresses, appropriate X-ray elastic constants have to be measured. Since these X-ray elastic constants may depend on the metallurgical state, deformation, and entire specimen history, errors in stress values may result if the constants are not measured for representative material states. In the present work, it is shown that in some cases these errors may be large. The X-ray elastic constant, S sub 22 1 nuE, has been measured for the 211 CrK sub alpha reflection from an Armco iron sample which had been previously deformed by rolling 69 pct. reduction in thickness and for the 211 CrK sub alpha and 310 CoK sub alpha reflections from a 1045 steel specimen which had been previously elongated in tension. The measured elastic constant for the Armco iron specimen was 40 pct. lower than the value calculated from the average of the Reuss and Voigt values.
- Physical Chemistry
- Metallurgy and Metallography