PSI - Issue 50

V.P. Gulyaev et al. / Procedia Structural Integrity 50 (2023) 100–104 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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1. Introduction The relevance of improving the regulations for the operation and diagnosis of various technical systems is due to the expansion of the industrial company economic activities in the Arctic and subarctic regions of Russia with a long period of low climatic temperatures as stated by Kostyuchenko (2017), Arabey (2010), Vorobyov et al (2012). The required reliability of power elements of machines and structures is determined by their rational metal consumption. The minimum possible value of the safety factor should be established by experimental and theoretical study of the limits of structural materials potential service properties when calculating the strength of machine parts and structures. The high efficiency of X-ray diffractometry is well known for revealing the features of the crystal lattice deformation of structural materials in the field of an elastic stress-strain state as indicated by Kotelkin et al (2016), Tashkinov and Shavshukov (2018). At the same time, issues related to the use of the characteristics of the X-ray lines diffraction profile for diagnosing the materials bearing capacity have not been sufficiently studied, in particular, the features of the influence of operation climatic conditions of materials on structural and substructural changes in the crystal lattices of metals loaded under stresses. 2. Purpose of the study The main purpose of this investigation is an experimental study of the crystal lattice reaction of structural materials samples with a BCC (body-centered cubic) and FCC (face-centered cubic) lattice, experiencing long-term operational static loads in natural climatic conditions. 3. Research methodology The following materials were chosen for the experiments: steel 08ps (Table 1), aluminum AD1 (Table 2), copper M1 (Table 3). The elastically stressed state was created in sets of 3 flat samples (working part 50× 4.5× 1 mm) interconnected in series in a single chain of one material by a vertically tensile static load. According to the research program, two batches of 08ps steel samples, AD1 aluminum samples and M1 copper samples were prepared. The first batch (4 sets of the same material, 12 sets in total) was subjected for long-term static loads in an open climatic area (Yakutsk, RF), the second (also 12 sets) - indoors with normal conditions. A constant tensile stress  = 0,9  0,2 arose in the working part of I set samples under the action of the load. II set:  = 0,7  0,2 , III set:  = 0,5  0,2 , IV set  = 0,3  0,2 . Table 2. Aluminum AD1 chemical content Chemical content, wt. % Si Mg Cu Fe Mn Ti Zn Al 0.3 0.05 0.05 0.3 0.025 0.15 0.1 99.3 The profiles of diffraction lines from the samples polycrystalline structure were determined by a Rigaku Ultima IV X-ray diffractometer with a high-precision horizontal goniometer in the operating mode of the X-ray tube of the diffractometer: voltage U = 40 kV; current I = 40 mA, in the angles range 2  = 123,00  … 125,00  from the second order reflection planes (hkl) = (220). The initial profiles of diffraction lines were obtained on samples subjected to recrystallization treatment. The profiles are approximated by the pseudo- Voigt function in the coordinates « I – 2  », Table 1. Steel 08ps chemical content Chemical content, wt. % Si Mn Cu 0.3 As Ni S C P Cr Fe 0.05-0.17 0.35-0.65 0.08 0.3 0.4 0.05-0.11 0.035 0.1 0.98