Rev.Adv.Mater.Sci. (RAMS)
No 1, Vol. 29, 2011, pages 68-82


A.G. Ermachenko, R.Ya. Lutfullin and R.R. Mulyukov


The most urgent problem of engineering and its advanced branch of aerospace engineering is the efficient use of materials and increased service life. Creation of aircraft engines of new generation requires the development of absolutely new technological processes for producing articles characterized by increased reliability and service life providing high metal utilization.

In this respect, titanium alloys, due to their high specific strength and corrosion resistance, are the most widely used structural materials, especially in such branches of engineering where material savings play a dominating role, in particular, aircraft engine- and ship-building and medicine. The spectrum of articles produced includes complex shape blades and discs for gas turbine engines, flanges, hollow cylinders, etc. During exploitation the above-mentioned articles are subjected to very high and low temperatures, very large structural loads and the influence of aggressive media etc. The above stated tasks can be effectively solved by introducing advanced highly efficient and low-waste technologies of metals working based on the use of the unique phenomenon of superplasticity. The forging in superplastic conditions enables one to reduce sharply the expenditures on costly alloys as well as to simplify the machining. At the same time, the enhanced exploitation characteristics of the articles produced can be achieved. The paper presents an experience of wide implementation of the technology for producing die forgings out of titanium alloys. The application of the technology provides:
1. Decreasing metal consumption by a factor of 2 - 5;
2. Decreasing labor intensity of machining by 30-60%;
3. Increasing service life by a factor of 1.5-2.
The method combining superplastic forming with pressure welding (SPF/PW) is very efficient for processing titanium alloys. The developed method essentially expands the available potentialities and creates new ones. It provides decreasing labor intensity and material consumption and can be used successfully for producing complex profile light-weight structures required for aerospace industry.

Superplastic strain processing allows hollow fan blades to be produced from titanium alloys. The process efficiency is increased by decreasing the processing temperature from 0.7Tmeltimg to 0.45Tmeltimg due to the use of nanostructured semi-products. The labor intensity of the process of hollow blade production and its power consumption can be reduced by 40% while the structural strength of an article processed can be increased by 10-15%.

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