Smolyakov A. Formation of amorphous-crystalline and quasicrystalline states in metal alloys under laser heating

The object is the formation of metastable amorphous-crystalline, crystalline and quasicrystalline states in conditions of rapid surface heating of metal alloys. The purpose is the study of the influence of heating rate and cooling rate during pulsed laser treatment of amorphous alloys or pulsed laser alloying of metals on formation processes of amorphous-crystalline and quasicrystalline states. Methods - X-ray structure phase analysis, metallographic, microhardness determination, resistometric, magnetometric, scanning electron microscopy. calculate -theoretical analysis of crystallization processes. It is established that crystallization of amorphous alloys of Fe-B system during pulsed laser heating can occur under the explosive mechanism. An empirical criterion for the crystallization of amorphous alloys by such a mechanism is proposed. It was found that increasing in heating rate during thermal action on amorphous alloys reduced the probability of metastable phases formation in such alloys. It is established that pulsed laser treatment of iron-based amorphous alloys in external magnetic field leads to irreversible laser repetition of magnetic induction anisotropy due to the anisotropy of atomic pairs, It is established that laser alloying of aluminum with powders mixtures of copper and iron, copper and cobalt and also cobalt and nickel leads to the formation of dispersed heterophasic structure in laser alloying zone, and one of its components is stable quasicrystalline phase. New method for modeling the quasi-periodic structures is proposed, which are related to Fibonacci sequence type. It is established the sufficiency of using only three indices (NML) for describing powder diffraction patterns from quasicrystals with symmetry axes of the 10th, 8th and 12th order. Sphere - educational process, research in the field of non-equilibrium phase transformations, mechanical engineering.