X-ray diffraction characteristics of five materials for stress measurement

Abstract

This paper presents the laboratory X-ray diffraction characteristics of five materials: carbon steel (Q235), austenitic stainless steel (1Cr18Ni9Ti), martensitic stainless steel (A335P92), Al alloy (LY12), and Ti alloy (TA15) in X-ray diffraction stress measurement. The difficulty in accurately determining actual stress is illustrated by two diffraction peaks with low diffraction intensity that occur in laboratory X-ray diffraction stress measurement. Stress measurements by both laboratory X-ray diffraction and strain gauges methods were conducted by using uniform strength beams of the five materials. A comparison between measured results and analytical/theoretical results was made to examine laboratory X-ray diffraction characteristics of the five materials for stress measurement. The measurements show that austenitic stainless steel, Al alloy, and Ti alloy present two diffraction peaks in X-ray diffraction stress measurement. Although the CrK a diffraction peak of the {220} plane of austenitic stainless steel is apparent, the stress calculated from this peak does not represent the actual stress; however, the CrK b diffraction peak of the {311} plane, in spite of the lower peak-back ratio, can be used to obtain the actual stress. For the Al alloy, only the CrK a peak of the {222} plane can represent the material's stress. Two diffraction peaks of the Ti alloy measured by CoK a radiation can be used to calculate its actual stress. Hence attention should be paid to which X-ray diffraction peaks can be used for actual stress determination.

Positron Annihilation Study of Defects Induced by Various Cutting Methods in Stainless Steel Grade 304

“…The presence of the subsurface zone (SZ), physical properties of which differ from those in the interior of a material [1] may influence the performance of the surface in service. For inspection of such alternations profilometry, microscopy, hardness testing, SEM, TEM [2] X-ray diffraction can be used [3,4]. Positron annihilation spectroscopy is seldom used for this purpose; however; it is a widely used technique for detecting of the defects at the atomic scale [5][6][7][8].…”

Slow Positron Beam Studies of the Stainless Steel Surface Exposed to Sandblasting

“…It allows to recognize defects sized from 0.1 to 1 nm and their concentrations at the level of 10 −7 . For detection of point defects PAS seems to be more eective than X-ray diraction (XRD) [2], scanning (SEM) or transmission electron microscopy (TEM) [3]. Nowadays, slow positron beams allow to study the adjoined surface layer of ca.…”