Spongy titanium alloyed with oxygen for the production of titanium alloys

We study the influence of alloying of spongy titanium with oxygen on the structure, mechanisms of fracture, and mechanical properties of titanium. It is shown that, within the range of concentrations 0.05–0.30%, oxygen insignificantly affects both the structure and the mechanism of fracture of cast titanium but strongly increases its strength with preservation of plasticity within the admissible range specified for standard titanium alloys of this grade. Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 44, No. 3, pp. 78–80, May–June, 2008.     

Modeling the process of redistribution of alloying elements in titanium alloys in interaction with gas media

Translated from Fiziko-Khimicheskaya Mekhanika Materialov, No. 3, pp. 55–58, May–June, 1988.     

Structural study of lithium titanium mixed oxides prepared by sol-gel process

A structural study, using TGA-DSC analysis, X-ray diffraction, Raman scattering and FT Infrared absorption, is performed on mixed titanium lithium oxide with 20% of lithium prepared by sol-gel process. The structure is investigated as a function of the annealing temperature. At low temperatures the sample is in the anatase phase and transforms to the rutile phase near 500°C. The crystallite size of rutile TiO₂ increases from 40 to 100 nm as the temperature increases. However the size increase presents some discontinuity at temperature around 600°C. At thermal treatment temperatures from 500°C to 850°C the presence of LiTi₂O₄ in the sample is clearly observed. Finally at 1000°C the sample is composed by a mixture of rutile TiO₂ and Li₂Ti₃O₇.     

Evaluation of heat release in the process of pulsed mechanical hardening of titanium alloys

We estimate the heat flows and distributions of temperature in titanium alloys in the course of their pulsed mechanical treatment. It is shown that, in the case of application of hardening tools made of 12Kh18N10T stainless steel, the heat flow directed into the hardened surface increases, which results in the additional heating of the surface layers to higher temperatures and, hence, in the growth of the depth of the hardened layer. An important role played by shear strains and mass transfer in the process of surface hardening of titanium alloys by pulsed mechanical treatment is discussed. Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 44, No. 3, pp. 99–102, May–June, 2008.     

Particle defects and related properties of metallic powders produced by plasma rotating electrode process

Flowability, particle size distribution and particle inner pore features for powders of Ti-6Al-4V, 316-steel, and Co-29Cr-6Mo alloys produced by plasma rotating electrode process (PREP) at various rotation speeds are analyzed by using scanning electron microscopy (SEM) and synchrotron X-ray computed tomography (CT). The results show that powder flowability is related to particle size distribution, surface morphology and dynamic friction coefficient of the alloy itself. This results in the higher powder flowability at low rotation speed than that at high rotation speed. Average particle size is roughly proportional to the square root of the reciprocal of rotation speed. In addition, particle size has an important effect on the particle porosity and the number faction of hollow powder in coarse powder is obviously larger than that in fine powder. Meanwhile, the alloy composition also plays a key role on porosity due to the various surface tension of alloys.     

用铅强化钛合金的探讨

探讨铅在钛合金中的强化效果，由于铅和钛在密度，蒸汽压，熔点方面相差太大，因此带来真空熔炼含铅钛合金十分困难，因此至今尚无人对含铅钛合金的强化效果进行研究，笔者由于基本解决了这一难题，因此有可能对这一问题进行初步研究。     

Correlation between the thermal change of resistance and the process of devitrification of glassy titanium based alloys

Investigations were carried out on the temperature dependence of electrical resistance of glassy alloys based on titanium: 52% Ti, 39% Cu, 8% Ni and 1 wt.% Si (A); 39% Ti, 51% Cu, 10 wt.% Ni (B); 60% Ti, 13% Cu and 27 wt.% Ni (C); 50% Ti, 45% Cu and 5 at.% Ni (D), from room temperature up to 30–40 K above the crystallization temperature. It was shown that the temperature coefficients of resistance in the glassy state region are negative for alloys A, C and D and positive for alloy B. After crystallization, with all alloys except C, coefficients are positive. A clear correlation exists between the stepwise process of crystallization of the glassy state and the change of electrical resistance. Each step of devitrification is followed by a discontinuous change (decrease) of the resistance which is caused by the increase of the mean free path of electrons because of the growth of the ordering of the alloy structure.     

Oxidation behavior of FeAl alloys with and without titanium

The influence of Ti addition on the high temperature oxidation behavior of FeAl intermetallic alloys in air at 1000°C and 1100°C has been investigated. The oxidation kinetics of FeAl alloys was examined by the weight gain method and oxide products were examined by XRD, SEM, EDS and EPMA. The results showed that the oxidation kinetic curves of both Ti-doped and binary Fe-36.5Al alloys could be described as different parabolas that followed the formula: (W/S)² = K _p t + C. The parabolic rate constant, K _p values are approximately 2.4 and 3.3 mg² cm^–4 h^–1 for Fe-36.5Al alloy and about 1.3 and 2.0 mg² cm^–4 h^–1 for Fe-36.5Al-2Ti alloy when oxidizing at 1000°C and 1100°C respectively. The difference between Fe-36.5Al and Fe-36.5Al-2Ti alloy is not only in the surface morphology but also in the phase components. In the surface there is only -Al₂O₃ oxide for Fe-36.5Al alloy while there are -Al₂O₃ and TiO oxides for Fe-36.5Al-2Ti alloy. The effects of Ti addition on the oxidation resistance of FeAl alloy were addressed based on the microstructural evidence.     

Optimal characteristics of electrospark alloying with eutectic electrode alloys

Summary Optimal values have been determined for the specific treatment time for unit area and for the treatment mode in electrospark alloying with an electrode made of an alloy in the Fe-Mn-C-B system, for which an Elitron-20 apparatus was used. The results are related to the erosion characteristics and the wear resistance in the coatings.Translated from Fiziko-Khimicheskaya Mekhanika Materialov, Vol. 27, No. 6, pp. 84–86, November–December, 1991.     

Adhesive and morphological characteristics of carbonate hydroxyapatite prepared from a model human synovial fluid on titanium alloys

Carbonate hydroxyapatite has been synthesized from prototype human synovial fluid and its surface characteristics on titanium have been evaluated. We have studied the effect of suspension composition on the morphological and surface characteristics and quality of the coatings and examined the influence of dopants (silicate ions and gelatin) on the properties of the coatings.