The state of research of titanium alloys: their mill-proucts, processes and applications in Ukraine, Russia and Kazakhstan (further CIS) is analyzed. The CIS titanium industry has become an important contributor to the world titanium market such as aerospace, chemical and marine (shipbuilding) industries. Fundamental studies on the complex nature of titanium-based materials are gradually shifting to applied research to develop and scale up advanced alloys, processes and new applications.

Temeaure conditions and corresponding techological parameters at which the ingots of round and rectanuar cross-section the homoeeous structure free of rough coumnar crystallines was formed were deermined by mathematical models of heat transer processes during elecron-beam remelting. Techoogy and equipment were deveoped for prouction of large-scale ingots of 1.2 m diameter and 4.5 m length directly from unrushed titanium spongy cakes. The quality of ingots both of commerial pure and alloyed titanium corresponds to ASTM B348-00 standard requirements.

The possibility to control different titanium alloy grades structure during thermo-hydrogen treatment is shown. The structure formation process in shaped castings of ВТ20Л alloy under additional hydrogen alloying was examined. It is shown that depending on hydrogen content during thermo-hydrogen treatment the transformation from large lamellate structure to fine lamellate structure having ?-particles of some micrometers to nanometers size is possible. The mechanism of phase and structure transformations in titanium alloys having the increased contents of ?-eutectoid stabilizer (Ti–12Cr) and aluminum (ВТ6, ВТ23) under the influence of hydrogen was examined. The possibility of development of composite structure consisting of ?-phase and TiCr2 intermetallide compound or non-coherent particles of ?2-phase and ?-phase, depleted by aluminum, is shown.

Structure and physicomechanical properties of a number of Ti–Si–Zr, Ti–Si–B, Ti–Si–Ga eutectic alloys were studied. It was shown that eutectic Ti–Si–Zr alloys with higher Zr content reinforced by dispersed (Ti,Zr)2Si silicides with sizes of about hundreds nanometers in comparison to alloys based on Ti5Si3 silicides demonstrate the improved mechanical properties. For the first time the as-cast Ti–Si–Zr–Sn eutectic alloy with RT plasticity of ~1.7 % was obtained. Formation of superdispersed eutectics based on ternary Ti6Si2B compound in Ti–Si–B alloys allows us to obtain titanium composites with improved high-temperature properties and elasticity modulus (of about 150 GPa and 165 GPa during additional alloying), that can be perspective for the development of novel titanium high-temperature resistant materials with higher rigidity. Study of gallium and silicium joint effect in Ti–Si–Ga alloys showed the possibility to produce titanium materials based on (a-Ti (a2-Ti3Ga)+Ti5(Si,Ga)3 binary eutectics with high temperature resistance.

The methods of thermodiffusion nitrocarburizing of titanium have been investigated. The possibility to realize nitrocarburizing in ?-region of titanium is shown. It was established that optimization of temperature-time and gas-dynamic parameters of nitrocarburizing together with a certain method allows to improve the quality and properties of the layer.

For different structure modifications of Ti–8Al–1.4Si–2.2Zr alloy it was established that the increase of test temperature promotes the increase of cyclic fracture toughness ?Kfc, however leads to decrease of the fatigue threshold ?Kth. At a temperature of 20?C the coarse lamellar structure of cast modification overbalances the fine grained structures of deformed materials in the middle and high stress intensity range, but only in the middle range –at temperature 700?C. Quenching from ?-phase region of ?-forged (90%) alloy increases the value of ?Kth at 20?C 2 times and ?Kfc at 700?C 1.6 times in comparision with the as-cast structure.

Peculiarities of microstructure and mechanical properties of commercial pure ВТ1-0 titanium after Local (surface) Rapid Heat Treatment (LRHT) with different fraction of heated above ?-transformation temperature (T?) layer were studied. It is established that ?-phase with the increased average grain size was formed in the surface layer in which transforaion occurred. Such a phase exhibits a decreased microhardness, while microhardness increased in the transition layer between zones heated above and below T?. The growth of the zone volume fraction heated above T? was accompanied by monotonic growth of tensile strength and decrease of relative elongation, while reduction in area was still approximately on the same level. The 100% material heating above T? was also characterized by the fatigue strength increase 1.5 times as compared with initial annealed condition. Summarizing all results it was concluded that changes in mechanical properties of LRTH-treated ВТ1-0 were obviously caused by the formation of high-level accumulated thermal stresses, which appeared as a result of a very fast heating and cooling (rate of both was about 400? C/s).

The diagram of isothermal decomposition of metastable ?-phase (TTT) of Ti–Al–Nb based alloy with a composition Ti–22Al–26Nb–0.5Zr–0.4Mo at.% was constructed in the temperature range from 600 to 900?С and holding time up to 64 min. The experimental methods were SEM, X-ray diffraction and durometeric analysis. The morphologic features of the product phases were analyzed.

The method for processing Ti–6.5Al–3.5Mo–1.7Zr titanium alloy is proposed. It is possible to increase by it the conventional yield strength of the alloy by 25% and ultimate strength by 15% at 400...550?С, correspondently, in comparison with conventional strengthening treatment. The method consists of several steps: specimen hydrogenation, deformation, quenhing, ageing and dehydrogenation vacuum annealing. The paper considers the phase compoition and microstructure after each step of treatment, since strength enhancement is caused by formation of the special structure state. The structure consists of fine (?+?)-lamellas within ?-grains 20...40 ?m in size and ?-phase precipitations with chemical composition close to the ordered Ti3Al interetallic compaund. It has been established that the structure and properties of the alloy do not change after additional annealing at 500?C, 100 h.

The possibilities of development of resource-saving direct technology of c.p. titanium sticks manufacturing by means of direct phasic straining of titanium sponge are investigated. Some schemes of basic technological operations were elaborated and experimentally examined. They are as follows: the high-temperature degassing of titanium sponge including determination of temperature-time parameters of the degassing process; the development and producing of a set-up for high-temperature vacuum compaction of titanium sponge; the pilot pressing (2 MN) of sticks made from consistent blank with obtaining experimental stick samples of ?30 mm; the pilot rolling of blanks with obtaining strips of thickness 2.0 mm.

The spongy titanium alloying with oxygen is considered. The influence of oxygen on structure, mechanisms of fracture and mechanical properties of titanium are invesigated. It is found that alloying with oxygen in the range of concentrations of 0.05%… 0.30% does not influence the structure and mechanism of the cast titanium. The considerable influence of oxygen is demonstrated by the substantial increase of the ultimate strength with saving plasticity in the admissible range set by the standard for titanic alloys of the appropriate grade.

The prospects of the use of Ti–Fe–O–N composition are considered for creation of economically alloyed of (?+?) titanium alloy with the strength level of 700… 1000 MPa and high technological plasticity. The maximum concentrations of alloying elements which provide the acceptable complex of strength characteristics are presented and optimum composition of Ti–1.5Fe–0.49O–0.05N alloy is proposed. The technologial and operating characteristics of the new alloy are analyzed and the conclusion about the alloy perspective use in many branches of industry is done.

It is shown that mechanical properties and structure of semi-finished work-pieces of the ВТ22 alloy are formed at the stage of hot deformation and depend on kinetics and morphology of the structure generation. The ambiguous, mainly harmful, effect of the presence of grain boundary ? and ?-precipitates on the properties the alloy of semi-finished work-pieces, especially of large-scale ones, is established. This fact requires the regulation of such structure inhomogeneity in technical specifications for supply and inspection.

The corrosion-electrochemical behaviour of (?+?) titanium BT-6 alloy coating and after high-dose nitrogen(E = 30 keV) with ion beam density 2•1017 cm–2 with subsequent annealing in vacuum and boron (E = 100 keV) with a beam density of 1•1015 cm–2, nitrogen and boron and also ion-plasma titanium nitrides coating has been studied in solutions of hydrochloric and sulphuric acids. It has been shown that surface modificaion increases the corrosion resistance of titanium alloy in highly concentrated solutions of acids, however, the resistance of the titanium nitrides coating of the thickness up to 10 ?m is insignificantly lower in comparison with an implanted alloy.

The new high-strength T110 titanium alloy is shown to have good welding ability. The welded joints, made by electron-arc welding are of equal strength with a base metal. The strength level of the welded joints, prepared by argon-arc welding, is not less than 90...95% of the base metal strength. To provide higher mechanical properties, welded joints of T110 alloy must be simply annealed at 750°C for 1 h and cooled in air.

The heat flows and temperature distribution of the titanium alloys during mechanical-pulse treatment are evaluated. It is shown, that the tools made of 12H18N10T stainless steel the heat flow directed to treated surface increases thus leading to surface layers heating to the higher temperatures and, correspondingly, to increasing of the hardened layer depth. The important role of shear deformation and diffusion mass transfer under mechanical-pulse treatment of titanium alloys is discussed.

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Deformation behaviour of ВТ6 alloys produced by powder metallurgy and ingot metallurgy processes was studied. It was established that under tensile testing at room tempeature both materials demonstrate the same evolution of dislocation structure and deformation behaviour. Deformation and strengthening of powder material and ingot metallurgy material with a lamellar microstructure is controlled by BCC ?-phase following composite strengthening mehanism. Powder materials demonstrate ductile fracture mechanism independently of sintering temperature. Residual pores in powder material are the places of crack initiation.

Heat resistance of complex-alloyed titanium alloys with 4.5…11 wt.% aluminium has been studied in cast and deformed states at 800?C for 50 h. It has been shown that alloying influences equally the cast and deformed metal wherever initial structure changes the oxidation kinetics of the deformed alloy. In this case, divided deformed structure forms the adhesion-strength scale, which provides high heat-resistance under long-term holding time.

Simultaneous effect of hydrogenation and preliminary plastic deformation (PPD) at 623 K by tensile and combined tension on the cleavage stress of the heat-resistant steel 15Х2МФА was investigated. Hydrogenation was carried out as before and as well after PPD. It was found by the TEM microscopy method that PPD, irrespectively of the loading type and hydrogenation mode, decreases distance between low-angle boundaries, increases its dislocation density and bainite microstructure off-orientation. Hydrogenated after PPD does not effect on the steel cleavage stress. PPD by tension and combined tension of preliminary hydrogenated steel decrease the cleavage stress proportionally to dislocation density in low-angle boundaries.

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The systems of steel 20 with nickel and zinc coatings in 3% NaCl, distilled water and 45•10–3% H2SO4 + 0,14% H2O2 + 5•10–6% K2Cr2O7 solution was investigated with the use of capillary probes, filled by these environments. It is shown that after their application there are no errors in measurements in the volume of electrolyte. Low conductivity of electrolyte and dissolution of metal in active state are the necessary condition of the identical measuring of local electrode potentials. It is shown that the accuracy of local micro-electrohemical measuring in a drop of electrolyte is better than in its film.

An effective new method of stress intensity factor estimation in a ferromagetic solid is proposed. A good agreement of stress intensity factor obtained by the proposed method for a circular crack with well known accurate magnetoelastic solution is shown. Some important solutions for crack stress intensity factor in ferromagnetic solids by using the proposed method are obtained.