PSI - Issue 65

Prokopyev L.A. et al. / Procedia Structural Integrity 65 (2024) 170–176 Prokopyev L.A., , Andreev Ya.M., Semenov S.O., Lukin E.S. / Structural Integrity Procedia 00 (2024) 000–000

175

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As can be seen from Figure 3, the modified value of the radius of the plastic zone is similar to the well-known plastic energy absorption abilities of the selected materials.

4. Results and discussion

The influence of temperature on the size of the plastic zone at the crack tip was assessed using data on the yield strength of materials at various temperatures. Analysis shows that with decreasing temperature the yield strength increases, which leads to a decrease in the plastic zone. This in turn may promote the transition from ductile to brittle failure due to insufficient plastic deformation to dissipate energy around the crack tip. It has been shown that in addition to the characteristics of the crystalline structure of materials, the basic properties of the material, such as the yield strength of the material, can also be the cause of the cold brittleness of materials. According to fracture mechanics calculations, for some materials the size of the plastic zone decreases significantly with decreasing temperature. This phenomenon can be assessed by calculation methods using data from simple material tests. Therefore, the obtained result can be used to develop new effective methods for assessing the cold resistance of materials. It is proposed to use a dimensionless value equal to the ratio of the size of the plastic zone at low temperatures to the size of the plastic zone at t=20 ℃ . This indicator can quantitatively assess the effect of temperature on the size of the plastic zone, as one of the indicators of the cold resistance of the material. To develop more accurate and effective methods for assessing and improving the properties of materials at low temperatures, it is necessary to separately study all the factors affecting the cold resistance of the material: loading rate, plastic zone at the crack tip, type of crystal lattice, features of the stress-strain state, and so on. The results of the study may improve the understanding of processes occurring at low temperatures.

5. Conclusion

The ratio of the size of the plastic zone at low temperatures to the size of the plastic zone at t=20 ℃ can be used to quantify the change in the size of the plastic zone with decreasing temperature. This study contributes to a better understanding of the relationship between operating temperature conditions and the strength characteristics of materials, which is especially relevant for engineering applications in cold climates and for improving methods for diagnosing and assessing the cold resistance of materials.

Acknowledgements

The reported study was funded by Ministry of Science and Education of Russian Federation, Project 122042000005-4 in the frames of Program for Basic Research of the Siberian Branch of Russian Academy of sciences. The work was carried out using scientific equipment of the Shared core facilities of the Federal Research Center ‘Yakutsk Science Center SB RAS’

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