The effect of side limiters (shaping blocks) on the formation of the structure and hardness of AISI 308LSi stainless steel workpieces obtained by multilayer build-up welding in an argon environment has been studied. The studies were carried out on specimens deposited using graphite limiters, copper limiters and without limiters. As a result of numerical simulation, it was found that the lowest temperatures of the specimen metal are observed when using copper limiters, and the highest when using graphite limiters (different thermal conductivity of materials) in comparison with the temperatures of the specimen obtained without limiters. With the use of graphite limiters, most of the specimen’s metal is in the temperature range of austenite formation (45%) and a more uniform growth of structural elements is observed, without sharp transitions between the deposited layers, in contrast to the other two types of specimens. The high value of the thermal conductivity of copper leads to an increase in the difference in the size of the dendrites between the central and peripheral side parts of the deposited specimen. The highest values of hardness are observed in the specimen obtained using graphite blocks, due to the more active diffusion of δ-ferrite into austenite by an average of 12%, compared with the other investigated specimens, despite the overall increase in size dendrites. The technology of electric arc multilayer build-up welding with the use of shaping graphite blocks makes it possible to produce a workpiece with a uniform structure and properties. The above makes it a promising direction in electric arc additive manufacturing.
The surface of an AM60 (Al—5.5, Zn—0.2, Cu—0.009, Fe—0.005, Si—0.1, Ni —0.002, Mn—0.3 wt %, Mg—the rest) magnesium alloy was exposed to a low-energy high-current electron beam. After the irradiation, the content of the β-phase (Mg17Al12) decreases and the aluminum content increases in the alloy surface layer. After the exposure to the electron beam, the corrosion resistance of the alloy in a 1-molar NaCl solution increases significantly compared to the initial state. The physical reason for an increase in the alloy corrosion resistance after exposure to the electron beam is the higher corrosion resistance of the oxide film formed on the alloy surface due to the increased aluminum content.
Using scanning electron microscopy, X-ray phase analysis, and hardness measurement we investigated the structure, phase composition, and mechanical propert