RAW MATERIALS. TITANIUM SPONGE
AN OVERVIEW OF METHODS FOR NITANIUM SPONGE PRODUCTION
V. Nechaev, A. Tsaplin
A traditional industrial chloride technology is a complex, multi-stage and energy intensive, therefore, a development of the alternative ways for low-cost titanium obtaining is a very promising and actively developing field. 16 electrolytic, 2 plasma and 9 metallo-thermic methods of titanium obtaining were found, many of them are in an active stage of development. There are no reports on the development of any of these projects to pilot or industrial scale. The industrial chloride technology continues to play a defining role in the production of high quality titanium.
Keywords: titanium sponge, the Kroll process, traditional, alternative technology.
WOULD TITANIUM BE CHEAPER TOMORROW? ON PROSPECTS OF IMPLEMENTING CONTINUOUS PROCESS OF MAGNESIOTHERMAL TITANIUM PRODUCTION
S. Lupinos, S. Grischenko, D. Prutskov, M. Kotsar, A. Alexandrov
Consideration has been given to the tendencies of the of titanium production development by the method of magnesium recovery over the past decade. The main positive and negative aspects analyzed associated with the growth of cycle productivity of recovery and vacuum separation apparatus. The possibility of intensification and the main tasks in the way of hardware design method of continuous titanium production based on the analysis of kinetics of the main steps of the implementation process it was shown.
Keywords: titanium tetrachloride, titanium, magnesium, recovery, vacuum separation, recovery and separation apparatus.
VIBRATION RESISTANCE OF TITANIUM PARTS AND ASSEMBLIES OF POWER EQUIPMENT
V. Travin, L. Lysenko, A. Kudryavtsev, L. Ivanova
Some material science problems of multi-cyclical endurance increasing for high-strength weldable pseudo-alpha-titanium alloys, used in vehicle steam turbines, are examined in this article. Vibration test results for parts and assemblies made of deforming and casing alloys are presented too. Methods of vibration stresses increasing are considered for all-welded working while’s blades. The impact of working vibration on static strength special specimens was researched for increasing details reliability estimation.
Keywords: pseudo-a-titanium alloys, multi-cyclical endurance, vibration tests, designing practices.
FORMATION OF STRUCTURE, PHASE COMPOSITION AND MECHANICAL PROPERTIES IN TITANIUM ALUMINIDE Ti2AlNb-BASED ALLOY UNDER HEAT TREATMENT
S. Skvortsova, O. Umarova, D. Anishchyuk, V. Smirnov
The effect of high-temperature heat treatment on structure and mechanical properties of the deformed semi-finished product – the rod with diameter of 60 mm – from heat-resistant Ti2AlNb-based alloy was studied. It was shown that the change of cooling rate on a high-temperature step of the treatment had a great influence on structure parameters, hardness, strength and plasticity of the alloy.
Keywords: heat-resistant titanium ortho-alloy, heat treatment, structure, phase composition, strength, plasticity.
REGULARITIES OF ISOTHERMAL PHASE TRANSFORMATIONS IN NEAR b-TITANIUM ALLOY WITH HYDROGEN
S. Skvortsova, G. Zaynetdinova, G. Gurtovaya, V. Zasypkin, A. Shalin
The mechanism and kinetics of isothermal phase and structural transformations in TS6 titanium alloy with hydrogen were studied in this work. It was shown that hydrogen alloying provided precipitation of intermetallide from b-phase and prevented formation of α-phase. It was stated that b-phase in the alloy cooled from b-field possessed a minimal stability at the temperature of 700°C. b-solid solution split took place on pre-precipitation stage on microvolumes depleted with chromium and enriched with hydrogen and the other ones enriched with chromium and depleted with hydrogen; formation of the intermetallide occurred in the last case. The effect of treatment conditions on morphology and preferable regions for precipitations of intermetallic compound was determined.
Keywords: titanium intermetallide, structure, phase composition
Semi-products manufacturing technologies
THE PROSPECTS FOR DEVELOPMENT AND IMPROVEMENT OF POWDER METALLURGY
A. Alexandrov, S. Kuznetsov, G. Demchenkov, E. Afonin
Ultra-fast cooling is achieved by minimizing the size obtained by the method of centrifugal spraying of granules, to achieve a very fine microstructure and homogeneity of the chemical composition of the granules, which further affects the properties of future details. Ultrafast cooling opens the possibility to improve the ductility of intermetallic alloys through shredding patterns.
Keywords: metallurgy of granules, titanium alloys, rate of crystallization, centrifugal atomization of the rotating workpiece, microstructure.
LIQUID FORGING – IMPULSE BULK PRESSURE CASTING METHOD
Metal liquid forging called Impulse Bulk Pressure Casting method may influence significantly on yield increase as it allows transfer from the melt directly to a complex shape part in one conversion stage. At that the metal structure obtained by this method may be nanocrystalline or amorphous, i.e. such that can’t be obtained by a conventional casting or conversion process.
Keywords: liquid forging; impulse bulk pressure casting method; impulse die forging; amorphous and nanocrystalline melts; composite materials.
Semi-products treatment technologies
EFFECT OF A COMPLEX PROCESS TECHNOLOGY ON STRUCTURAL STATE, PHYSICOCHEMICAL AND OPERATIONAL PROPERTIES OF TITANIUM ALUMINIDE BASE ALLOY
A. Mamonov, Yu. Chernyshova, V. Pozhoga, S. Sarychev, A. Neiman
In this work there was investigated the effect of a complex technology comprising thermo-hydrogen treatment, vacuum ion-plasmous nitriding and titanium nitride coating on a number of operational properties in Ti-14Al-3Nb-3V-0,5Zr (wt.%) alloy based on Ti3Al titanium aluminide. It was stated that the structural state of volume and surface formed in the samples increased resistance of the alloy to salt corrosion and intensive erosion in solid microparticles flow. It was shown that vacuum ion-plasmous nitriding improved heat resistance of the alloy at the temperature of 700°C, and deposition of TiN coating provided a sharp decrease of oxidation rate during exposure at this temperature.
Keywords: titanium aluminide, vacuum ion-plasmous nitriding, titanium nitride, salt corrosion, heat resistance, erosion.