Issue 77

N. S. Kondratev et alii, Fracture and Structural Integrity, 77 (2026) 230-246; DOI: 10.3221/IGF-ESIS.77.14

(determined according to relation (10)) amounted to 0.42% for identification and 1.15% for verification. Further computational experiments were carried out in the temperature range 200 340 − C ° . All identified parameters are given in Tab. 1.

Figure 2: The average size (diameter) of subgrains av d of pure nickel vs time t ; simulation data – solid lines, experimental results [33] – dots.

Symbol

Parameter

Value

Source

Geometric parameters of the initial subgrain structure

Initial average subgrain size

0.25 μm

0 av d

[33]

Uniform distribution hypothesis [5, 24] Data-based identification [25]

ψ

0.8 0.9 −

Subgrain sphericity

Average angle of mutual misorientation of subgrains

av θ

2.29 °

Subgrain coalescence model parameters

b

Burgers vector modulus Self-diffusion coefficient

0.255 nm

[37] [38]

0 D

4 1.6 10 − ⋅

2 1 m s −

Activation energy of self-diffusion

19 5.51 10 − ⋅ J

Q

Identification

Subgrain migration model parameters

Maximum subboundary misorientation angle Pre-exponential term in relation (3) Activation energy of boundary migration Average value in relation (5) High-angle boundary energy Geometric correction factor Shape factor

m θ

°

15

[5]

,0 hag m

4 1 1 m J s − −

15 7.5 10 − ⋅

Identification

b Q

19 0.528 10 − ⋅ J

Identification

α

1.5

[5]

/ z sb p e

1 m −

[30, 31]

7 2.1 10 ⋅

, sb m e

2 J/m

[39]

0.930

β

1.0 Identification Table 1: Physical and geometrical parameters of the migration and coalescence models.

237