Anomalies in Measurement of Residual Stress by X-Ray Diffraction.
NORTHWESTERN UNIV EVANSTON ILL DEPT OF MATERIALS SCIENCE
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Residual stresses are expected to lead to a linear dependence of the interplanar spacing, d, on sine squared psi where psi is the sample tilt and the stress can be obtained from the slope of this line. As a result of the linear dependence a two-tilt method is often employed to obtain the stress. However, when a specimen is subjected to extensive plastic deformation large deviations from a straight line can occur and a two-point method can lead to an erroneous stress determination. The results reported here show that 1 this is more likely to occur in homogeneous materials than in multiphase materials 2 the oscillations follow closely the variation in peak intensity due to texture 3 the oscillations are caused by microstresses which are due to an orientation effect as suggested by Weidemann. A simple, easy-to-use procedure has been developed and tested to correct the data and obtain the correct macrostress. The materials used were Armco iron, steel and ordered Cu3Au. Modified author abstract
- Metallurgy and Metallography
- Test Facilities, Equipment and Methods