OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 24 No. 4 2022 Based on dependences (1) and (2), having determined the absorption function on the basis of experimental data, it is possible to restore the image of the volume of the body under study. To do this, you need to solve an equation of the form: 0 ln ( , ) . L I f x l dl I = ∫ (3) Currently, to solve this equation, software packages that allow to reconstruct images of the objects under study based on tomography or laminography data with filtered back projection methods [17] (based on the Radon transform, Algebraic Reconstruction Technique, etc.,) are used. Examples of laminography application for the analysis of metal alloy samples Computed laminography was used originally as a method for studying elements of microsystem technology, namely printed circuit boards. Its application to solve this problem is relevant at the present time. Later, the method was used in the study of cultural heritage objects [18, 19], in paleontology [20], materials science [21], and other research areas. In materials science the laminography method is in demand for solving problems related to the study of objects made of polymer composites [22] and metal alloys. The effect due to the phase contrast can be used to highlight interfaces between different materials with poor absorbency. The essence of the proposed solution is to change the distance from the radiation source to the sample which ensures the appearance of interference effects on the detector. This approach helps to improve the sharpness of the boundaries of the sample components. Examples of using the laminography method for the analysis of a number of alloys are discussed below. In situ studies of plastic deformation of metal plates The method of computed laminography provides a unique opportunity to represent the mechanisms of crack propagation in sheet materials and fixation of internal damage in three dimensions of the sample. In some works synchrotron computed laminography was used to study the processes of crack formation and destruction of metal plates [23–27]. Fig. 9 shows a diagram of one of the devices used for loading samples with stress concentrators. Figure 10 shows the diagram of station ID19 located at the European Synchrotron Radiation Facility (France) equipped with devices for implementing the laminography method [28]. This station was used to study the mechanisms of destruction and development of cracks in aluminum alloy samples with a loading device (Table 2) [29]. Figure 11 shows the scheme of deformable samples. During the tests the volume of formed defects, its reorientation and sizes according to Feret’s shape factor were evaluated. Fig. 9. Schematic of the device used for loading a specimen with a stress concentrator [27]
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