Методика дослідження механізмів зародження кристалів у розплавах металів в залежності від їх обсягу та форми

• Date: 2025
• Main Authors: Chistyakov, O. V., Nuradinov, A. S., Nogovitsyn, A. V., Sirenko, K. A., Baranov, I. R., Nuradinov, I. A.
• Format: Article
• Language: Ukrainian
• Published: Physico- Technological Institute of Metals and Alloys of the NAS of Ukraine 2025
• Subjects: прозорі органічні середовища; розплав; температура перегріву; переохолодження; механізм зародження кристалів; швидкість зародкоутворення; структура
• Online Access: https://momjournal.org.ua/index.php/mom/article/view/2025-2-5
• Journal Title: Metal Science and Treatment of Metals

This work is devoted to the study of the mechanisms of crystal nucleation in metal melts depending on their shape and volume. The method of physical modeling was applied, using low-temperature (tmlt. ≤ 70 ° C) Wood’s metal alloy and transparent organic media such as camphene and diphenylamine. The experiments were conducted on two types of test specimens: flat samples of small thickness (δ = 0.2 mm) and bulk samples of larger volume in glass tubes (Ø 8 mm).           The transparency of the media and the small thickness of the flat samples made it possible to visually observe the crystallization process and determine the degree of supercooling based on the coolant temperature at which the first crystal appeared. The supercooling level of the bulk samples was determined by characteristic features on their cooling temperature curve — namely, the appearance of plateaus due to the release of crystallization heat.  As a result of the study, it was demonstrated that the rate of nucleation in flat samples of model media directly depends on the activity of the mold wall surfaces. The activity of these surfaces, in turn, is significantly influenced by the degree of overheating of the model melts above the liquidus temperature and the level of their supercooling. In experiments with bulk samples, it was found that, in addition to the activity of the mold wall surfaces, the dependence of the supercooling of the studied media on their overheating is also affected by factors such as the activity of present impurities, as well as fluctuations in temperature and density.