International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

The structure formation features of the bulk glass alloy Zr41,2Ti13,8Cu12,5Ni10Be22,5 under conditions of melt casting in a copper mold and subsequent heating of amorphous ingots, are studied. It is shown that for certain parameters of the model (the thickness of the ingot and its heating rate), the main contribution to the total crystallized volume fraction passes from frozen crystal growth processes to the processes of nucleation and growth of new crystals. Regardless of the dominant crystallization process during heating, amorphous ingots of the Zr41,2Ti13,8Cu12,5Ni10Be22,5 alloy are crystallized to form a coarse crystalline structure.

Using an original mathematical model the calculate analysis of the relationship of thermal modes of castings production with crystallization kinetics and microstructure parameters of the alloy Cu₄₇Ni₈Ti₃₄Zr₁₁ is made. It is shown, that at cold mold casting in castings of different thickness are fixed three types of microstructure: amorphous with inclusions of so-called "quenching nucleus", amorphous- crystalline and polycrystalline with microscale size of the crystals. For castings with a completely crystallized nanocrystalline structure proposed method of isothermal quenching melts, which is realized by casting the melt into the preheated mold. Determined values of the initial mold temperature interval provides for the formation of castings having a grain size of 100 nm for justifiable from an economic point of view intervals.

Using the method of mathematical modeling, the effect of the initial temperature of the mold on the thermal conditions and kinetics of crystallization of chill castings of Cu₄₇Ni₈Ti₃₄Zr₁₁ alloy was investigated. According to the results, established that the value can have a significant effect on the final structure of the ingots. Depending on the value of, it is possible to provide thermal conditions under which formation of amorphous, amorphous-crystalline and fully crystalline states is possible. It is shown that the changes in the initial temperature of the mold are reflected in the final parameters of the microstructure of the resulting ingots, the average crystal size can vary from tens of nanometers to several micrometers.