Accession Number : AD0783677

Title :   Anomalies in Measurement of Residual Stress by X-Ray Diffraction.

Descriptive Note : Technical rept.,

Corporate Author : NORTHWESTERN UNIV EVANSTON ILL DEPT OF MATERIALS SCIENCE

Personal Author(s) : Marion,R. H. ; Cohen,J. B.

Report Date : 01 JUL 1974

Pagination or Media Count : 49

Abstract : 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)

Descriptors :   *Residual stress, *Plastic deformation, *X ray diffraction, Measurement, Stresses, Steel, Iron, Copper alloys, Gold alloys, Intermetallic compounds

Subject Categories : Metallurgy and Metallography
      Test Facilities, Equipment and Methods

Distribution Statement : APPROVED FOR PUBLIC RELEASE