The Measurement of Plastic Strain by X-Ray Diffraction Using the Gaussian Curve Parameter

Abstract

When annealed metals are cold worked, their diffraction lines broaden due to nonuniform lattice strain and small particle-size. The broadening of the diffraction line caused by plastic deformation was measured by using the Gaussian curve parameter (GCP), which is a constant in a Gaussian curve fitted to the diffraction peak and can be determined from only five to fifteen X-ray intensities around the diffraction peak. Annealed mild steels were plastically deformed by tension, compression, and torsion. The GCP increases with increasing logarithm of equivalent strain along a straight line for all the specimens. The use of the GCP allows a rapid and nondestructive measurement of plastic strain in annealed mild steels. The relationship between the GCP and the half-width is also given.