PSI - Issue 50

A.S. Smirnov et al. / Procedia Structural Integrity 50 (2023) 266–274 A.S. Smirnov, A.V. Konovalov,V.S. Kanakin and I.A. Spirina / Structural Integrity Procedia 00 (2022) 000 – 000

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Fig. 2. Experimental (blue curves) and model-calculated (black curves) time dependences of flow stress for the V95 alloy deformed at 400 °C according to forms of loading I (a), II (b), and III (c).

The EBSD data testify that, during deformation according to dependence 1 (see Fig. 4a), the volume portion of dynamic recrystallization is 0.011 and that it is 0.085 for dependence 2 and 0.253 for dependence 3. In order to clarify the coefficients of model (1), for a more accurate description of dynamic recrystallization, the identification was carried out by the volume portion of dynamic recrystallization in the alloy using the minimization function

N m z z j i j i j i    1

N

j



  V T V T V T s s e s s r    s e

  s

n 1

m 

n







1

i



a , ,a 

min.







0

14

s (3) Here, s is the number of the time dependence of strain rate (see Fig. 4a) involved in the calculation; m is the number of dependencies involved in the calculation ( 3  m ); s r V and s e V are the calculated and experimentally determined volume portion of dynamic recrystallization for the s -th dependence, respectively. The addend in function (3) is the deviation of the calculated values of the volume portion of dynamically recrystallized grains from the experimental values   s s r V T , s T is the time of the end of the deformation experiment. Figure 2 shows the time dependences of flow stress, calculated by model (1) with the coefficients obtained in the minimization of function (3). The values of these coefficients are given in Table 1. The average relative deviation of the calculated flow stress values from the experimental ones is 4.2%. At the same time, the average relative deviation of the calculated volume portion of dynamic recrystallization during deformation according to patterns 1 – 3 is 7.6%. Thus, the volume portion of dynamic recrystallization r V is 0.012 for dependence 1 (see Fig. 4a) 0.095 for dependence 2, and 0.248 for dependence 3. Hence, the model allows us to describe the rheological behavior and the volume portion of dynamic recrystallization with acceptable engineering accuracy and thus to predict the flow j j   1 1