OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 24 No. 4 2022 Figure 5 shows examples of scans for three diffraction maxima of the B2 phase. It follows that the presence of a crystallographic texture leads to the presence of texture maxima for the diffraction peaks (100) and (111). This fact makes it impossible to approximate the diffraction band by a function. Therefore, the analysis of residual stresses was carried out by analyzing the deviation of the average value of the intensity of the diffraction maximum from its zero-position (at the absence of internal stresses). a b c Fig. 5. Diffraction maxima (100) (a), (111) (b) and (210) (c) in the coordinates « – 2θ» of B2 phase after uniaxial compression of alloy AlCoCrFeNi by 18 % Figure 6, a shows the dependence of the residual lattice distortions on the applied stresses. The largest increase in stresses occurs along the [100] direction. This is due to the anisotropy of the crystal lattice of the B2 phase. At an applied stress of ~2,500 MPa, the residual distortion of the lattice along this direction was 2.25 %. In addition, the sample before deformation (i.e., in the cast state) is also characterized by the presence of lattice distortions, which is associated with the presence of thermal stresses during cooling of the ingot. An analysis of the Al0.6CoCrFeNi alloy showed that the B2 phase of this sample is characterized by a more signifi cant lattice distortion. According to the obtained results (Figure 6, b), the lattice distortion under an applied stress ~2,500 MPa was 5.5 %. This fact is in good agreement with the results of optical metallography (Figure 2). Since no cracks or other traces of destruction were found in the structure of the Al0.6CoCrFeNi alloy (Figure 2, c), it can be concluded that the structure did not relax due to its destruction. At the same time, the presence of cracks in the structure of the AlCoCrFeNi alloy (Figure 2, d) indicates to its partial relaxation. This is indicated by the values of crystal lattice distortions (Figure 6, b). The analysis of the deformation of the crystal lattice also makes it possible to estimate the values of the elastic modulus of alloys. However, since the energy of plastic deformation is stored in the structure as both macro- and microstresses, the analysis of the change of the positions of diffraction peaks makes it possible to estimate only the upper limit of possible values of the elastic modulus. However, even such estimate makes it possible to qualitatively compare the properties of the phases of the alloys. According to the obtained results, the maximum value of the elastic modulus of B2 phase of the AlCoCrFeNi alloy along the [100] direction is 111 GPa. At the same time, the maximum value of elastic modulus for the B2 phase of Al0.6CoCrFeNi alloy along the same direction is equal to 46 GPa. Thus, the lattice of the B2 phase in the AlCoCrFeNi alloy is signifi cantly less compliant than the lattice of the same phase in the Al0.6CoCrFeNi alloy.
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