OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 24 No. 4 2022 a b c d Fig. 2. Results of metallographic studies: AlCoCrFeNi alloy before deformation (a), deformed by 12% (c); Al0.6CoCrFeNi alloy before deformation (b) after 53% compression (d) Estimation of residual macrostresses of crystalline phases of alloys AlCoCrFeNi and Al0.6CoCrFeNi was based on the analysis of changes in the shape of diffraction rings with a change in the azimuth angle (). In other words, the lattice parameter was estimated for each angle . However, in this case, the positions of the diffraction maxima should be clearly distinguishable. Figure 3 shows an example of one-dimensional diffraction patterns obtained in this work. According to [11, 12], the composition of the AlCoCrFeNi alloy includes two phases characterized by cubic crystal system: disordered phase (space group 3 ) Im m and ordered phase (space group 3 Pm m, or B2 type in Strukturbericht terms). Since the lattice parameters of these phases are identical, the diffraction maxima have the same angular positions. Therefore, the analysis of lattice distortions of the AlCoCrFeNi alloy is possible only for phase peaks with a primitive lattice. In this work, the calculation was carried out using three diffraction maxima of 3 Pm m phase: (100); (111) and (210). The overlap of the diffraction peaks of 3 Im m and 3 Pm m phases is also typical for the diffraction pattern of the Al0.6CoCrFeNi alloy. At the same time, this alloy also includes a phase with the space group 3 Fm m. Therefore, the analysis of the lattice distortions of the primitive cubic phase was carried out only by the diffraction maximum (100) for Al0.6CoCrFeNi alloy. The analysis of residual macrostresses was carried out according to the obtained 2D diffraction patterns. The diffraction pattern was represented as a scanning in the coordinates “2θ — χ” (Figure 4). This type of diffraction pattern makes it possible to estimate the lattice distortions by the position of the diffraction maxima along the angle χ. For this, the approximation of the diffraction band by a periodic function is optimal.
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