Titanium №3 2013
INFLUENCE OF PLASTIC DEFORMATION AND HEAT TREATMENT ON THE STRUCTURE OF TWO-PHASE TITANIUM ALUMINIDE PRODUCED BY EBM WITH BORON AND LANTHANUM ADDITIVES
G. Grigorenko, S. Akhonin, A. Severin, V. Berezos, S. Grigorenko, V. Lakomskii, T. Solomijchuk
Investigation of the influence plastic deformation and heat treatment on the structure of alloyed two-phase γ-titanium aluminide produced by EBM with boron and lanthanum additives. Microstructure was studied and X-ray microprobe analysis of wrought and heat-treated samples was conducted. It is shown that hot plastic deformation promotes structure refinement and fragmentation of boride inclusions in the wrought sample, compared to the initial cast structure. After heat treatment a bimodal structure with uniformly distributed particles of borides and lanthanum oxide forms in the alloy.
Keywords: electron beam melting, titanium aluminide, deformation, heat treatment, structure, boron, lanthanum.
PHYSICOCHEMICAL AND TECHNOLOGICAL FOUNDATIONS OF THERMOSTABLE BIMODAL STRUCTURES FORMATION IN HEAT-RESISTANT TITANIUM ALLOYS AND TITANIUM ALUMINIDE-BASED ALLOYS UPON REVERSIBLE HYDROGEN ALLOYING
A. Mamonov, S. Skvortsova, E. Agarkova, O. Umarova
Principal physicochemical and technological aspects of bimodal structure formation in heat-resistant titanium alloys and in alloys based on a2-phase upon thermohydrogen treatment are considered. Diagrams of phase composition being formed in the alloy–hydrogen systems at different temperature are given. A number of important effects are described; the effects are realized in alloys upon reversible hydrogen alloying and determine morphological and size parameters of the structure. The base scheme is given for thermohydrogen treatment which forms bimodal structure, and the peculiarities of structure formation during the treatment are described as well. There are also the examples of structures for different alloys and their mechanical properties.
Keywords: heat-resistant titanium alloy, intermetallide, thermohydrogen treatment, bimodal structure, phase diagram, complex technology, ordering, diffusion, volume effect.
COMPOSITE STRUCTURE FORMATION IN TITANIUM ALLOY WITH HIGHER ALUMINIUM CONTENT UNDER HYDROGENATION ANNEALING
S. Skvortsova, V. Spektor, O. Gvozdeva, V. Zasypkin, A. Petrov
The influence of hydrogen content on formation of phase composition and structure in titanium alloy with higher aluminium content was investigated. It was shown that (a(a2)+b)- composite structure can be formed under certain temperature-content conditions when the ordering process takes place in separated microvolumes of a-phase enriched by aluminium up to the content close to stoichiometric one.
Keywords: titanium alloy, phase composition, structure, hydrogen, hydrogenation annealing.
STRUCTURAL PECULIARITIES AND FUNCTIONAL PROPERTIES OF NITRIDE COATINGS ON DETAILS FROM TITANIUM ALLOYS IN MEDICAL PRODUCTS
V. Spektor, E. Lukina, S. Sarychev, N. Mitropolskaya, A. Safaryan
The structure of nitride coating on heads of hip joint endoprosthesis from VT6 titanium alloy was studied by means of raster electron microscopy with energy dispersive and wave spectroscopy. It was shown that the coating had grain structure with TiN grain size of about 60 nm, and the thickness of the coating was about 300 nm after application of coating by condensation method during 5 minutes. It was stated that increase of nitriding process period up to 45 minutes led to the growth of nitride coating thickness and allowed to improve wear resistance and corrosion resistance properties of heads.
Keywords: titanium alloy, nitriding, titanium nitride, structure, raster electron microscopy, wear resistance.
STRUCTURE AND INHOMOGENEITY OF CHEMICAL COMPOSITION OF TITANIUM PSEVDO-α- ALLOY INGOTS WEIGHTING UP TO 17 TONS
A. Kydriavtsev, S. Petrov, A. Khachaturian, L. Machishina
The paper presents the results of structure researching of titanium psevdo-α- alloy ingots weighting up to 17 tons. During the study reflected electrodes analyzer (EBSD method) and a radiography heat – dispersive spectrometer (MPCA method) were used together. It was observed that during crystallization zonal types of liquation are absent. Forming of a significant micro inhomogeneity during α - and β stabilizing components distribution due to slow cooling at β→α+β- transformation was also shown.
Keywords: macrostructure, chemical inhomogeneity, distribution of elements between a- and b-phases, crystallographic orientations, electron backscattering diffraction method (EBSD)
ALLOYS VT20L & VT23L FATIGUE PROPERTIES FORECASTING BY FRACTURE SURFACE QUANTITATIVE ANALYSIS
I. Vozdvizhensky, A. Mamonov, E. Kuryshev
Interrelation of titanium cast alloys VT20L & VT23L fracture surface quantitative parameters and fatigue limit of this alloys had been investigated. Mathematical models forecasting alloys VT20L & VT23L fatigue limit by impact elasticity samples fracture surface quantitative parame ters with low error had been suggested.
Keywords: titanium, cast alloys, fractography, mechanical properties, quantitative analysis, properties predictions.
Semi-products manufacturing technologies
TECHNOLOGICAL ASPECTS OF SOME WAYS REDUCING THE COST OF TITANIUM PRODUCTS
G. Kolobov, V. Pavlov, A. Ovchinnikov, V. Ivanov
Possible ways to reduce the cost of titanium products was considered. Highlights three areas: the use of scrap titanium alloys and low-grade titanium sponge, economical use of doping and for the manufacture of ingots and products of new technologies.
Keywords: titanium, ingots, scrap, smelting technology, refining, alloying, titanium sponge, crushing, grinding, powder, mechanical properties.
Semi-products treatment technologies
SURFACE MODIFICATION OF TITANIUM GRANULAR ALLOYS UNDER THE ULTRASONIC EXPOSURE
A. Logacheva, D. Kasyanova, I. Logachev, E. Sulman, V. Matveeva
In the article results of granules surface modification for Titanium alloys, such as ВТ18У, ВТ25У, СТ6У after the ultrasonic exposure under the different test mode are presented. For the ultrasonic exposure were used granules in the following size ranges: (+40-125) µm, (+125-180) µm, (+180-250) µm. The study of the ultrasonic exposure influence on Titanium alloys granules composition was made by using X-ray photoelectronic spectroscopy method. The surface of granules was compared before and after modification, including chemical composition changes.
Keywords: titanium alloys, surface modification, granules, ultrasonic exposure, X-ray photoelectronic spectroscopy method, chemical composition.
DEVELOPMENT OF EFFICIENCY EVALUATION METHOD FOR TITANIUM EXPORT
O. Ugarova, I. Ilychev, V. Brinza, A. Aleksakhin
The issues of economic efficiency evaluation for execution of export transactions are considered in this article. Current methodological terms of export efficiency evaluation don’t provide effective decisions on the expediency of export transactions execution. The new methodological terms based on the terms of marginal analysis were developed which allow to determine economically effective transactions. New methodology enhances precision of efficiency evaluation for export transactions and minimizes the risk of making ineffective decisions.
Keywords: efficiency, export, margin, marginal profit, facilities, manufacturing capacity, titanium.
Events and anniversaries
To the 60-year anniversary Alexandr Rylov
To the 75-year anniversary Anatoly Stroshkov