Methods and technologies for improving the Magnesium alloys casting

Abstract

Purpose. Rational selection of alloying elements for the development of new magnesium based alloys with enhanced properties and technologies that provide high-quality casting.Research methods. Metallographic and X-ray research methods. The study of the surface tension of the melt by the sessile drop method. Determination of mechanical properties under tension (GOST 1497-84) and long-term strength at elevated temperatures (GOST 9651-84).Results. The expediency of alloying a magnesium alloy with any other element is determined by the phase dia­gram of the system under consideration, the properties of the strengthening phases, the nature of the alloy structure and its stability during heating, as well as the nature of diffusion processes occurring in alloys with changes in composition and temperature. Based on the analysis and generalization of the binary phase diagrams of the elements with magnesium, the expediency of alloying a magnesium alloy with one or another element was established. At the same time, to ensure the best combination of mechanical and heat-resistant properties of cast magnesium alloys, the following conditions must be met: the formation of complex-alloyed solid solutions, the strengthening of the alloys by dispersed particles and the creation of an optimal structure by the heat treatment.When smelting magnesium alloys, complex processes of interaction occur between the charge materials and alloying elements, fluxes, shielding atmosphere and modifiers. Therefore, for obtaining high-quality casting, the role of technological factors in the smelting, pouring and heat treatment of magnesium alloys is crucial.Scientific novelty. On the basis of the atomic-electronic structure of the elements, analysis of their binary phase diagrams with magnesium, a number of alloying elements that provide the best combination of mechanical and heat-resistant properties of cast magnesium alloys was determined.It is shown that improving the quality of magnesium alloy castings, that includes the use of properly selected technological modes of melting, casting, development of rational modes of crystallization and heat treatment, pro­vides a significant increase in their operational characteristics.Practical value. Improvement of mechanical and special properties of magnesium alloy castings due to the optimal use of charge components and rational technologies for the production of high-quality casting allows to significantly expand the fields of application of these alloys.