A fatigue level estimation method includes estimating a fatigue portion in a metal material, measuring a distribution of a misorientation in the fatigue portion, obtaining a specific area ratio of the fatigue portion based on the distribution of the misorientation in the fatigue portion, and obtaining an estimated fatigue level of the metal material based on at least one of the specific area ratio of the fatigue portion and a degree of change in the specific area ratio of the fatigue portion. The specific area ratio of the fatigue portion is a ratio of a specific area existing in a measurement area of the fatigue portion.

A computer-implemented method for identifying mechanical parameters of an object subjected to mechanical stress is provided. The method comprises a step of acquiring, by an imaging means, images of the object taken before and during the application of the mechanical stress, three steps of calculating the effects due to the stress carried out either on the basis of the modeling of the recorded images or on the basis of a theoretical mechanical modeling of the stress, a step of defining a functional equal to the difference between the two models and a last step of minimizing said functional so that the experimental model is as close as possible to the theoretical mechanical model. Additional measurements make it possible to refine the method.

An X-ray generator 110 irradiates with an X-ray beam onto a polycrystalline sample on a sample stage 113. An X-ray detector 116 including an array of X-ray detecting elements detects the intensities of diffracted X-rays which occur from the X-ray beam incident on the sample. A rotary drive rotates the X-ray generator, X-ray detector and sample-holding section so as to maintain a predetermined relationship between the angle formed by the sample surface and the incident X-ray beam, and the angle formed by the sample surface and the diffracted X-ray travelling toward the X-ray detector. A stress measurement section rotates, for a measurement of a stress value of the sample, either the X-ray generator and the X-ray detector or the sample stage so as to change the angle formed by the sample surface and the incident X-ray beam, while maintaining the positional relationship of the X-ray generator and the X-ray detector.

A scanning electron microscope includes a spin detector configured to measure spin polarization of a secondary electron emitted from a sample, and an analysis device configured to analyze measurement data of the spin detector. The analysis device determines a width of a region where the secondary electron spin polarization locally changes in the measurement data. The analysis device further evaluates a strain in the sample based on the width of the region. With a configuration of the scanning electron microscope, it is possible to perform analysis of a strain in a magnetic material with high accuracy.

The invention relates to a method for processing images obtained by a diffraction detector, of a crystalline or polycrystalline material, in which a first image of the material is acquired in a state of reference as well as a second image of the material in a deformed state. The invention is characterised in that, in a calculator, during a first step (E6, E12), a current elastic deformation gradient tensor F.sup.e is given a value determined by calculation, during a second step (E7), the current displacement field induced by the tensor F.sup.e is calculated, during a third step (E8), third digital values of a deformed image {hacek over (g)}(x)=g(x+u(x)) corrected by the current displacement field are calculated, and during an iterative algorithm, iterations of the second and third steps (E12, E7, E8) are carried out on modified values of the tensor r F.sup.e until a convergence criterion is met in relation to the correction to the current value of F.sup.e.

The present invention is a method for measuring a residual stress in a cast and forged steel product, the method using X-rays, including: irradiating a cast and forged steel product with X-rays; two-dimensionally detecting intensities of diffracted X-rays originating from the X-rays; and calculating a residual stress based on a diffraction ring formed by an intensity distribution of the diffracted X-rays detected in the detecting, wherein, when the residual stress is measured for each of a plurality of measurement positions of the cast and forged steel product, the residual stress for each of the measurement positions is calculated in the calculating based on the diffraction ring for each of the measurement positions and an X-ray elastic constant which varies for each of the measurement positions.

A tomography scanner includes at least one first emission source (GX1), one first matrix detector (D1), and a computer (C) arranged to produce an initial tomography of an object (E) based on radiographs arising from the first matrix detector, taken from various angles. The tomography scanner further includes a second emission source (GX2) and a second matrix detector (D2) arranged so that, when the object is subjected to a loading that is known at a given instant in time, the computer determines the changes in the object subjected to said loading based only on the information from the first radiograph of the object under loading arising from the first matrix detector, from the second radiograph of the object under loading arising from the second matrix detector and the initial tomograph, the first radiograph and the second radiograph being taken simultaneously at the same given instant in time.

A system for performing diffraction analysis, includes a mill for removing a surface portion of a sample, and an analyzer for performing diffraction analysis on the milled sample.

A high resolution grazing incidence X-ray diffraction technique for measuring residual stresses and their gradients as a function of depth in thin film materials on substrates or in bulk materials is disclosed. The technique includes positioning a material relative to an X-ray source and an X-ray detector, performing an Omega scan to determine an Omega offset, setting the incidence angle at a first target incidence angle based on the Omega offset and greater than the critical angle of the material, performing a grazing incidence X-ray diffraction scan, analyzing the results to identify diffraction peaks, selecting a diffraction peak, setting the incidence angle at a second target incidence angle based on the Omega offset and a desired penetration depth, performing two theta scanning on a range of two theta values around the selected diffraction peak, performing refraction correction, and determining residual stress values for the material.

A method for measuring the stress of a concave section of a test subject which comprises a metal and has a surface and a concave section, the method including: a detection step for detecting, using a two-dimensional detector, a diffraction ring of diffracted X-rays which is formed by causing X-rays to be incident on the concave section and to be diffracted by the concave section; and a calculation step for calculating the stress of the concave section on the basis of the detection results during the detection step. Therein, the detection step involves causing X-rays to be incident on each of a plurality of sites inside the concave section of the test subject, and detecting, using a two-dimensional detector, the diffraction ring formed by the diffraction of the X-rays by the concave section.