Enhanced assessment of technological factors for Ti-6Al-4V and Al-Cu-Mg strength properties

OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 23 No. 4 2021 a b Fig. 5. Evolution of parameters as a function of the stress amplitude for D16 ( Al-Cu-Mg ) samples with “1” and without a weld “2”; а ) evolution of the temperature and the average plastic axial strain; b) evolution of the temperature and the plastic axial strain amplitude It can also be seen from (Fig. 5, b ) that the weld in the alloy D16 samples leads to the fact that the amplitude of the axial plastic strain has a higher value in the samples with a concentrator. When the stress amplitude ( σ a ) is close to 160 MPa, the amplitude of irreversible deformations ( ) p xm  increases by 0.03 % for samples with a stress concentrator. With periodic deformation of samples with a weld by a symmetric stress cycle with an average component, the critical stress decreases by 38 %. For D16 alloy samples, the kinetics of changes in the average plastic strain and average temperature during cycling at “Step 3” of the program (Fig. 3) with a constant amplitude of the stress cycle σ a = 167 MPa was checked (Fig. 6). For a smooth D16 sample (Fig. 6, a), the average temperature increased monotonically during cycling (from ∆ T m = 0.4 °C to ∆ T m = 0.67 °C) at a constant stress amplitude σ a = 167 MPa. In this case, the value a b Fig. 6. Evolution of the temperature and the plastic average axial strain versus the number of loading cycles for the samples a) D16 ( Al-Cu-Mg ) without a weld; b) D16 ( Al-Cu-Mg ) with a weld