Analysing the influence of structure morphology on weld metal properties, searching for relationships through multifractal indices

DOI: 10.62564/M4-OS1733

Olha Shtofel^1,2, Viktor Holovko², Daniil Korolenko<sup>2

1</sup>National Technical University of Ukraine «Igor Sikorsky Kyiv Polytechnic Institute»
²E.O. Paton Electric Welding Institute, Ukraine


The orientation of the structure has a significant effect on mechanical properties. If the grains are oriented in the longitudinal direction, i.e., when deformed along the crystallographic planes, which characterise the direction of grain growth during crystallisation, the ductility, as well as the short-term and long-term strength of the alloy, increase. The orientation of the grains in the direction of maximum stresses eliminates the presence of transverse grain boundaries, so the development of cracks along the boundaries in the longitudinal grain orientation is more difficult than in the transverse or equilibrium structure. The paper shows a solution to the problem of finding the angle of inclination of crystallites, calculating their sizes on the example of a model; the connection with the fractal parameter and mechanical properties of the distribution by angles of misorientation of the real structure. The model contains several objects of an arbitrary elongated shape. The task is to determine the orientation of the grains by finding the angle of inclination of each object to the selected axis. The programme, written in phyton with the use of artificial intelligence, is designed to analyse objects of different geometries in the input image. The results of the work consist of two parts. The first part is the program code corresponding to the theory, and the second part is the analysis of the data obtained and comparison with the existing mechanical properties and fractal dimensions of the components. The programme includes: 1) Converting the image to a black-white scale. 2) Detecting various shapes in the image using a thresholding technique. 3) Calculating properties - the length, width, centroid, orientation and angle. 4) Create data files. Further processing of the data allows you to build distributions of orientation angles on a flat structure, analyse the mechanical characteristics and compare them with the fractal dimension of the images.

Keywords
orientation, structure, properties

Acknowledgments
Not provided

References
[1] I. M. Zhuravel, V. M. Maksymovych Quantitative analysis of grain orientation and elongation in metallographic images using Hough transforms, Scientific Bulletin of the National Technical University of Ukraine, 2018, vol. 28, no. 5 [2] I.S. Gakh, B.O. Zaderiy, G.V. Zvyagintseva, A.V. Zavdoveev, Y.V. Oliynyk Crystallographic and dimensional characteristics of weld structure elements of single crystals of heat-resistant nickel alloys, Journal of Automatic Welding, 2023, No. 9, pp. 3-10 [3] K. A. Yushchenko, B. A. Zadery, I. S. Gakh, A. V. Zviagintseva, O. O. Fomakin, and A. V. Zavdoveev, Welding of Single Crystals of Heat-Resistant Nickel Alloys as Innovations of Power Gas Turbines, Metallofiz. Noveishie Tekhnol., 2021, vol. 43, No. 10, pp. 1401-1415