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Comparative studies of the heat resistance of titanium, nickel, and carbon steel with coatings based on aluminides obtained by liquid-phase aluminizing with diffusion annealing at 850, 950°C were conducted. The influence of the holding time of aluminized samples of titanium, nickel, and carbon steel at 950°C on changes in their mass and oxidation rate was determined. [ABSTRACT FROM AUTHOR]

The heat resistances of titanium, nickel, and carbon steel with aluminum-based coatings produced by liquid-phase aluminizing with diffusion annealing at 850 and 950°C are studied and compared. The influence of the holding time of aluminized titanium, nickel, and carbon steel specimens at 950°C on the changes in their weight and oxidation rate is revealed. [ABSTRACT FROM AUTHOR]

The heat resistance of titanium with coatings based on titanium aluminides deposited by liquid-phase aluminizing followed by a high-temperature hold is studied. The effect of the duration of the hold of titanium specimens in an aluminum melt and of the duration of the high-temperature exposure of the aluminized specimens on the chemical and phase composition, structure and heat resistance of the coatings is determined. [ABSTRACT FROM AUTHOR]

Aluminizing process of titanium in aluminum melts A7 and AK12 was investigated. The influence of aluminizing regime on the structure and chemical composition of the coating on the titanium alloy VT1-0 was established. [ABSTRACT FROM AUTHOR]

The mechanical properties of a layered foam aluminum–titanium composite material produced by the filling of Al melt into molds with pore-forming fluorine fluxes and titanium fixtures are investigated. The shear strength of the composite is determined by the adhesive bond between Al and Ti as well as by the strength of the intermetallic transition layer formed at the interface of the metals. To improve the adhesive bond, titanium is coated with aluminum, and the strength of the intermetallic transition layer is enhanced by alloying it with Co through an Al melt used for aluminizing of titanium. The effect of cobalt alloying on the wetting and spreading of Al melt in titanium during the formation of a composite material is studied. It is shown that alloying with 3% Co reduces the area of spreading of aluminum over titanium. When the titanium surface is activated with the K2TiF6 and K2ZrF6 flux, the wetting of titanium with the melt increases with an increase in the cobalt content, and when activated with KF-AlF3 eutectic, it decreases. Alloying with 2% Co increases the shear strength of the composite owing to the hardening of the intermetallic transition layer. When Ti surfaces are activated with K2ZrF6 flux, the shear strength of composites has the maximum value, which is due to alloying of the transition layer simultaneously with Co and Zr. [ABSTRACT FROM AUTHOR]

The mechanical and damping characteristics of titanium–aluminum foam composite materials obtained via casting of a mold with aluminum filled with pore-forming granules and titanium fittings are investigated in this work. Titanium reinforcement of aluminum foam is shown to increase the strength of a foamed material, slightly increasing its density. The damping properties of titanium–aluminum foam composites are close to those of a solid metal at an increase in the titanium content in the composite. [ABSTRACT FROM AUTHOR]

The processes of wetting and spreading of zirconium-doped aluminum over titanium were studied under the conditions of the formation of layered aluminum-titanium composite materials with the activation of the surface of titanium with flux based on K2TiF6 salt. It is established that zirconium, owing to an increase in viscosity and a decrease in the fluidity of the melt, reduces the area of ​​spreading of aluminum over titanium. Doping the intermetallic layer between aluminum and titanium with zirconium leads to an increase in the adhesion strength of the composite layers. The maximum values ​​of adhesion strength are observed at a process temperature of 950°C and a zirconium concentration of 0.25%. [ABSTRACT FROM AUTHOR]

Titanium dissolution in the aluminum melt and synthesis of an intermetallic compound at constant temperature and pressure are numerically simulated by the molecular dynamics method. Owing to titanium dissolution, the TiAl intermetallic compound is formed near the interface between the titanium crystal and aluminum melt. Based on the theory of weak solutions, a mathematical model of titanium dissolution in the aluminum melt is constructed. Dependences of the diffusion coefficient, equilibrium concentration of titanium, and dissolution rate on temperature are obtained. [ABSTRACT FROM AUTHOR]

Abstract: EPMA and TEM analysis shows that there is a Ti transition layer around TiC particles in the α-Al grain center both in the usually solidified sample and in the rapidly solidified ribbon. Because the rapid solidification restrains the solute of the melt to diffuse before solidification, the rapidly solidified ribbon can conserve the instantaneous structure of the melt mostly, indicating that the Ti transition layer originates from the Ti transition zone in the melt. A new theory named as “Ti transition zone” theory has been proposed as a possible refinement mechanism for pure aluminum by Al–Ti–C refiner, and its formation model is given. The influence of the Ti transition zone on the melt viscosity was also discussed in this paper. [Copyright &y& Elsevier]