Electron beam melting and refining (EBMR) is one of the modern and widely used technologies which is employed industrially for melting and metal purification. Experimental investigations, computational modeling and optimization approaches are indispensable tools in the study of this ecological technology, for the development and optimization of effective technological schemes and their application to different materials as well as for reducing the price of the pure metals produced. On the basis of experimental and theoretical studies performed, data and results of practical importance for various applications of EBMR are obtained and summarized (for Cu, Ta, Hf, Ti, Au, etc.). The obtained results allow us to formulate requirements on the process parameters and are important and useful in view of studying, controlling and optimizing the quality and purity of the new materials obtained by recycling of metal scrap by EBM.
FEATURES FORMATION OF THE BORIDES TRANSITION METALS LAYERS BY AN ELECTRON-BEAM SURFACING OF SHS PRODUCTS IN VACUUM
The formation features of transition metals borides at high temperatures and low pressures were investigated and discussed the conditions of formation, structure and wear properties of boride layers on the surface, formed in electron beam processing in a vacuum.
CREATING NANOSTRUCTURED SUPERHARD AND HEAT-RESISTANT SURFACE LAYERS ON CARBON TOOL STEEL AT INFLUENCE TO INTENSE ELECTRON BEAMS
The saturation of the surface layers of metals and alloys boron is conducted with the purpose of increase of their surface hardness, wear resistance, etc. Multicomponent layers containing in its composition borides of refractory metals, as a rule, formed by the methods of chemical-thermal processing in the interaction boriding component with refractory or by saturation boron refractory impurities metal or alloy.
In this work, we studied the features of formation of vanadium and iron borides on the surface of instrumental steels U8A and R18 under the influence of intense electron beams in continuous and pulse modes.
Warm and hot compressive tests, bending test, measurement of density, heat capacity and thermal conductivityw ere applied to study of feature mechanical and physical properties of cast alloys Fe + (16,8 – 25,6) % Mn + (0 – 14,4) % Al + (0,02 – 2,18) % C + (0,001 – 0,135) % N.
This paper presents new methods of thermal processing of the aluminum alloys. It analyses the effects of boiling treatment of alloys Al–Cu and Al–Si in an oxidizing atmosphere on their microstructure, hydrogen content and the coefficient of linear thermal expansion (CLE). An increase of boiling time from 15 to 75 hours results in an initial increase in the hydrogen content in alloys later followed by a decline in the hydrogen content. These changes in the hydrogen content correlate with the dynamics of alloys’ microstructure and their CLE. This study shows that atmosphere with a high oxygen content induces an acceleration of diffusion processes in aluminum alloys. If boiling time does not exceed 30 hours, the hydrogen content in a solid solution and etchability of grain boundaries of α-solid solution decrease and intermediate phases get partially dissolved. We demonstrate that boiling treatment of aluminum alloys in an oxidizing atmosphere leads to a decline of the CLE measured under the temperature 50-450°С which is especially strong when measured under the temperature 250-350°С.