All-Russian Scientific Research Institute of Aviation Materials, Moscow, Russia

L. B. Khokhlatova, Head of a Sector, e-mail: admin@viam.ru
N. I. Kolobnev, Chief Researcher
E. A. Lukina, Senior Researcher

“All-Russian Institute of Light Alloys” JSC, Moscow, Russia

L. B. Ber, Chief Researcher

Anisotropy decrease in 1424 Al – Mg – Li-alloy sheets can be achieved by some ways. One of them was a combination of rolling in L and LT direction (cross rolling). The second way was an air quenching of 1424 sheets at the regulated rate after high temperature heating at solid solution treatment. A favourable distribution of the excessive S₁-phase with an exception of banded type was provided at this way. The most decrease of anisotropy can be achieved by forming the fully recrystallized structure in sheets, what was found difficulties in 1424 alloy, additionally alloyed with Zr and Sc. In the present work the possibility of producing a fully recrystallized structure in cold rolled sheets was investigated. To improve a technological plasticity a cold rolling was performed after preliminary annealing of hot rolled sheets. The technological plasticity was studied by means of determination a critical deformation degree at plane strain compression at room temperature. The phase composition of hot rolled and annealed sheets was investigated using TEM, SEM and X-ray analysis. The uniform fine-grained and fully recrystallized structure in sheets was obtained after rolling with preliminary annealing at 350–380 ^oC and final solid solution treatment. After the indicated above annealing the maximum volume fraction of the equilibrium S₁-phase precipitates was observed in the alloy. After cooling in air from the annealing temperature it was found a very small quantity of δ^′-phase and after slow cooling with the furnace this phase was practically absent. The fully recrystallized structure in sheets provides a substantial decrease of the tensile property anisotropy in three directions.

1. Fridlyander I. N., Khokhlatova L. B., Kolobnev N. I., Rendiks E., Tempus G. Metallovedenie i termicheskaya obrabotka metallov – Metal Science and Heat Treatment. 2002. No. 1. p. 3.
2. Fridlyander J. N., Kolobnev N. I., Khokhlatova L. B., Beresina A. L., Katko A. V., Haszler A. Texture and Grain Structure of Al – Li – Mg – Zr – Sc Alloy Sheets. Proceedings of ICAA-7. 2000. Vol. 2. p. 867.
3. Kolobnev N. I., Setyukov O. A., Khokhlatova L. B., Oglodkov M. S. Tekhnologiya legkikh splavov – Technology of light alloys. 2010. No. 1. p. 100.
4. Fridlyander I. N., Grushko O. E., Antipov V. V., Kolob nev N. I., Khokhlatova L. B. Alyuminiylitievye splavy (Aluminium and lithium alloys). Aviatsionnye materialy. Izbrannye trudy 1932–2007 : nauchno-tekhnicheskiy sbornik (Aviation materials. Chosen proceedings (1932–2007) : scientific and engineering collection). 2007. p. 163.
5. Khokhlatova L. B., Kolobnev N. I. Tsvetnye Metally – Non-ferrous metals. 2007. No. 2. p. 96.
6. Khokhlatova L. B., Kolobnev N. I., Antipov V. V., Karimova S. A., Rudakov A. G., Oglodkov M. S. Aviatsionnye materialy i tekhnologii — Aviation materials and technologies. 2011. No. 1. p. 16.
7. Vainblat Yu. M., Sharshagin N. A., Khokhlatova L. B., Kolobnev N. I., Bukharina N. V., Klimovich L. G. Development of Recrystallized Structure During Hot Deformation of Al – Mg – Li – Zr – Sc Alloy. Proceedings of ICAA-9. 2004. p. 383.
8. Antipov V. V., Kolobnev N. I., Khokhlatova L. B. Razvitie alyuminiylitievykh splavov i mnogostupenchatykh rezhimov termicheskoy obrabotki (Development of aluminium and lithium alloys and multistage regimes of thermal treatment). Aviatsionnye materialy i tekhnologii : yubileynyy nauchnotekhnicheskiy sbornik (Aviation materials and technologies : anniversary scientific and engineering collection). 2012. p. 183.
9. Fridlyander J. N., Kolobnev N. I., Khokhlatova L. B., Loechelt E.,Winkler P.-J., Pfannenmuller T. Study of Structure and Properties of 1420 Alloy Modifications for Sheets. Proceedings of ICAA-6. 1998. Vol. 3. p. 2055.