JSC “Kamensk Uralsky Metallurgical Works”, Kamensk Uralsky, Russia:

B. V. Ovsyannikov, Chief Metallurgist

Aluminium-lithium alloys have a unique combination of mechanical properties (low density, increased elastic modulus, and rather high strength properties), which make it possible to use these alloys as aircraft structural material and to improve aircraft performance characteristics. At the same time, aluminium-lithium alloys have a number of disadvantages: low plasticity on the verge of maximum strength, and low corrosion resistance, particularly in form of thin-walled semi-finished products. New aluminiumlithium alloy with increased plasticity and corrosion resistance was developed. It enables production of thin sheets and thin-walled sections, maintaining the strength and performance characteristics required for structural aircraft materials. Optimal chemical composition of the alloy allows to carry out almost complete transfer of copper into solid solution, which leads to significant decrease of volume ratio of gross intermetallic compounds of copper bearing phases and increasing of alloy plasticity. Additional alloying with alkaline-earth metals and limiting alkaline metals and gallium leads to more favorable conditions for shear deformation and increase of alloy plasticity. Introduction of vanadium, scandium and zirconium contributes to homogeneous fine-grained structure, providing the structural strengthening of semi-finished products and alloy parts, which makes it possible to achieve the required level of alloy strength properties. Introduction of argentum contributes to more equal distribution of strengthening phases in solid solution and more equal precipitation of dispersoids during ageing. As a result, both strength and corrosion alloy properties are increased.

1. Fridlyander N. I., Chuistov K. V., Berezina A. L., Kolobnev N. I. Alyuminiy-litievye splavy. Struktura i svoystva (Aluminium-lithium alloys. Structure and properties). Kiev : Naukova dumka, 1992. 177 p.
2. Ovsyannikov B. V., Popov V. I., Zamyatin V. M. In search of ways to increase Al – Li – Cu – Mg system aluminum-lithium alloy processing plasticity. Aluminium. 2007. No. 3.
3. Grushko O. E., Sheveleva L. M., Zhegina I. P., Basyuk S. T. Vliyanie primesey shchelochnykh i shchelochnozemelnykh metallov na strukturu i svoystva splava 1420 (Influence of admixtures of alkaline and alkaline-earth metals on structure and properties of alloy 1420). Voprosy aviatsionnoy nauki i tekhniki. Seriya: Aviatsionnye materialy = Issues of aviation science and technics. Series: Aviation Materials. 1988. No. 2. pp. 10–19.
4. Ovsyannikov B. V., Popov V. I., Zamyatin V. M. Splav na osnove alyuminiya (Aluminium-based alloy). Patent RF, No. 2310005. IPC С 22 С 21/00.
5. Ovsyannikov B. V., Popov V. I. Splav na osnove alyuminiya (Aluminium-based alloy). Patent RF, No. 2412270. IPC С 22 С 21/16. Applied: December 02, 2009. Published: February 20, 2011. Bulletin No. 5.
6. GOST 9.913–90. Edinaya sistema zashity ot korrozii i stareniya. Alyuminiy, magniy i ikh splavy. Metody uskorennykh korrozionnykh ispytaniy (State Standard 9.913–90. Unifom system of protection from corrosion and ageing. Aluminium, magnesium and their alloys. Methods of accelerated corrosion testings). Introduced: January 01, 1992. (in Russian).
7. GOST 9.904–82. Edinaya sistema zashity ot korrozii i stareniya. Splavy alyuminievye. Metod uskorennykh ispytaniy na rasslaivayushchuyu korroziyu (State Standard 9.904–82. Unifom system of protection from corrosion and ageing. Aluminium alloys. Methods of accelerated layer corrosion testings). Introduced: 1983–07–01. (in Russian).
8. GOST 9.021–74. Edinaya sistema zashity ot korrozii i stareniya. Alyuminiy i splavy alyuminievye. Metody uskorennykh ispytaniy na mezhkristallitnuyu korroziyu (State Standard 9.021–74. Unifom system of protection from corrosion and ageing. Aluminium and aluminium alloys. Methods of accelerated intercrystalline corrosion tests). Introduced: 1975–01–01. (in Russian).