PSI - Issue 50

R.S. Akhmetkhanov et al. / Procedia Structural Integrity 50 (2023) 11–16 R.S.Akhmetkhanov / Structural Integrity Procedia 00 (2019) 000 – 000

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Consider how the total perimeter of the filler grains changes (as a percentage of the image area) during mixing of the components. Table 3 shows these data. There data on change of mass volume of filler on a surface of a material in percentage relation are also given. As the components of the PCM are mixed, the mass fraction of the filler in the projection of the image decreases. The filler is evenly distributed throughout the entire volume of the material, whereas at the beginning of the process, the filler had a larger mass fraction closer to the surface. At the beginning of the process, the mass fraction of filler on the surface decreased and after 90 minutes of processing increased slightly from 18.36% to 18.82%, while the relative total grain perimeter decreased from 0.541 to 0.483.

Fig. 4. Borders of filler grains in PCM at various time of mixing of components (matrix and filler): a - 90 minutes; b - 120 minutes.

Table 2.Fractal dimensionality D of the PCM mixture image.

Processing time of the mixture, minutes

1

15

60

90

120

Fractal dimension D

1.6544

1.7515

1.7394

1.8229

1.7678

Table 3. Total perimeter of grains and relative mass volume of filler.

Mixing time, minutes

1

15

60

90

120

Total perimeter of grains Sp , % Total mass fraction of filler Sm , %

9.56

8.59

7.31

9.94

9.1

31.85

24.18 0.355

21.21 0.345

18.36 0.541

18.82 0.483

Relative index of the total perimeter of grains Sp/Sm

0.3001

5. Conclusion Thus, the given methods and their combination allow us to estimate the material structure by means of geometrical characteristics. The distribution of filler or matrix grains in the composite material, their spatial homogeneity in the material cross section, the scale significance of grain sizes and their number allow us to estimate the homogeneity of the material and the technological process. According to the obtained characteristics of grain distribution, their sizes and the degree of filling of the mixture surface filler, we can conclude that the last 30 minutes of treatment of the mixture material did not lead to a significant improvement in its homogeneity. Even the relative total perimeter of the grains decreased slightly, although the grain size distribution changed towards a decrease. This means that the ratio of the perimeter of the grains to their radius has decreased - the grain boundaries are less indented.