Russian researchers from the Institute of Metals Superplacticity Problems (Russian academy of sciences) developed a new technology for creating 3D and flat sheet materials with homogeneous nanostructure.

Studies of the Russian scientists showed that new materials simplified production of hollow-core constructions, such as blades of aircraft engine fans.

Scientists from the Institute of Metals Superplacticity Problems (located in Ufa, Bashkortostan Republic) designed a technology of integrated isothermal forging, which allowed making metals and alloys with regular grains of 300-400 nanometers in diameter. Mentioned alloys or metals can then be transformed into a flat sheet material with the same grain size by means of hot rolling technique. Size of a flat sheet is limited only by press mass – for instance, scientists successfully made titanium alloy sheets with dimensions of 1500 mm x1500 mm x2mm.

Experiments with new materials showed that a titanium alloy sheet with abovementioned dimensions had 15-25% better durability and fatigue resistance, than commercial sheet made from the same alloy with larger (micron-sized) grains. Moreover, this nanostructural crude material is suitable for such widely used processing techniques, as pressure welding and superplastic molding under temperatures, which are 250-300 degrees Centigrade lower than temperatures, usually required for these processes. In other words, this means that nanostructural layer, placed between production titanium alloy items, allows using pressure welding for these items under temperatures, lower than usual.

 

 

Scientists have also designed and built development types of light fan blades for turbo-jet aircraft engines – this project was a joint programme with engineers of the open joint stock company “Aviadvigatel”. The blade has lower weight than usual due to having a hollow core and containing reinforcing filler, made of flat sheet nanostructural titanium alloy. Mechanical strength characteristics of a hollow fan blade are about 90% of that of a solid one; however its critical sector loads are also 20% lower due to low weight. A hollow blade can be made at relatively low temperatures (650-750 degrees Centigrade), which can prevent formation of a fragile gas-saturated layer on the surface. Such layer actively forms, when temperatures exceed 750 degrees Centigrade, and is very hard to remove afterwards.

Researchers tend to think that metals and alloys, which have nanostructure and which were made by means of a new technology – integrated isothermal forging, can find applications in various fields of industry, in building and construction industry, for instance. The technique provides titanium alloy sheets of various sizes and can be easily adapted to any pressure equipment, already installed at a plant. The technology waits for customers to bring it into ordinary industrial life.

Source: Science & Technologies

Kizilova Anna