N. A. Vatolin

Carbide formation in aluminum melts processed by low-frequency elastic vibrations

The temperature and time conditions of carbide formation in binary aluminum melts subjected to elastic low-frequency vibrations transferred through a graphite vibrating piston are studied to develop an in situ technology for the production of composite materials. Our experiments demonstrate that the carbide-forming abilities of components dissolved in aluminum cannot be estimated from the changes in the standard free energies ΔGT of formation of their carbides from pure elements. Although energies ΔGT of formation of titanium and zirconium carbides from pure elements are close, only titanium dissolved in aluminum has a high carbideforming ability. This specific feature is used to synthesize titanium carbides in an aluminum melt and to produce aluminum-based composite materials hardened by titanium carbides.

Application of boron-containing materials in metallurgy

The main physicochemical characteristics of complex boron-containing ferroalloys are studied. The methods of their production are briefly described, and the advantages of their application to boron microalloying of steel are demonstrated.

Al-Sc-Zr Master Alloy and Estimation of Its Modifying Capacity

An Al-1.1 Sc-1.1 Zr (wt %) master alloy with a uniform distribution of micron and submicron particles of aluminide phase Al3(Sc1 − xZrx) has been obtained by exposing of equal amounts of commercial Al-Sc and Al-Zr master alloys to short-time actions of low-frequency vibrations transferred to the alloy via an irradiating plunger. Zirconium substitutes up to 50% Sc in aluminides and retains its L12 lattice. The modifying capacity of the experimental master alloy is tested on cast alloy (wt %) Al-8Zn-2.4Cu-3Mg. Intense grain refinement of this alloy is achieved by its modification with a certain amount of the master alloy. At a certain Sc + Zr content, a grain dendrite structure completely disappears in the alloy.

Structure of Al-Ti-C master alloys

A binary Al-Ti master alloy of hyperperitectic composition, whose structural characteristics ensure high modifying efficiency, has been prepared by the aluminothermy method. The treatment of the alloy by low-frequency vibrations (LFVs) and its interaction with the carbon emitter of LFVs in the process of crystallization lead to the formation of a ternary Al-Ti-C alloy containing titanium aluminide Al3Ti and titanium carbide TiC. The presence of these phases creates favorable conditions for the formation of solidification nuclei in the aluminum melt when using a ternary master alloy as a modifier. A comparison of the efficiency of the structure refinement when using experimental master alloys and the standard Al-Ti master alloy poured into a metallic chill mold has been performed.

Effect of time-temperature and low-frequency acoustic treatments of the melt on the structure formation in the Al-5% Fe alloy

Regularities of the structure-formation in the Al-5% Fe alloy under conditions of time-temperature and low-frequency acoustic treatments are studied. A 500-K overheating of the melt above the liquidus temperature was found to cause a sharp change in the conditions of formation of the solid phase at the solidification front and to initiate the formation of a metastable quasi-eutectic structure. An additional low-frequency acoustic treatment increases the effect of the melt undercooling. This leads to the formation of anomalous growth forms of the solid at the lower overheatings of the melt.

Solubility of vanadium from manganese vanadates in aqueous solutions of soda ash

It is shown that, in the course of developing the technology of pure vanadium pentoxide preparation from manganic vanadium-containing metallurgical slags, their oxidative roasting and cinder formation without alkaline additives are accompanied by the decomposition of spinelides with the formation of manganese meta- and pyrovanadates. Concentrated aqueous solutions of soda ash with an Na2CO3 concentration of 120–150 g/dm3 are accepted as a selective leaching reagent for vanadium from a cinder. Manganese metaand pyrovanadates are synthesized, and the procedure of their preparation is presented. The solubility of vanadium from manganese vanadates in aqueous solutions of soda ash at

New method for determining the Helmholtz energy of a reference system in the WCA method

C_{Na_2 CO_3 } = 150 g/dm^3

Formation of a Intermediate Order in Metallic Glasses and a Long Order in Nanocrystalline Alloys with Allowance for the Character of Binding and the Transformation of the Short Order in a Melt

CNa2CO3=150g/dm3 is studied at 20–95°C for pyrovanadate and at 85–95°C for metavanadate. It is shown that vanadium should be leached from converter manganic slags roasted without alkaline metal additives at a leaching solution temperature higher than 95°C. There is a possibility to increase the vanadium content in a leaching solution to 60–80 g/dm3. The results obtained are used in the development of the technology of vanadium leaching.