Central Research Institute of Structural Materials PROMETEY, Saint Petersburg, Russia

A. S. Oryshchenko, Chief Executive Officer
E. P. Osokin, Head of a Laboratory
N. N. Barakhtina, Leading Engineer

“Alcoa Samara Metallurgical Plant” JSC, Moscow, Russia

A. M. Drits, Executive Officer on Development of Business and New Technologies, e-mail: Alexander.Drits@alcoa.com
S. M. Sosedkov, Manager of a Technical Department

Welded aluminum-magnesium corrosion-resistant alloy 1565ч containing 5.1–6.0% of magnesium, 0.45–1.0% of zinc, 0.4–1.2% of manganese and some content of zirconium, chromium and titanium. Structure of metal and such mechanical properties as tensile strength, yield strength and impact toughness in the range of temperatures from 20 to –196 ^оC were investigated. Samples of 7 mm hot-rolled sheet at room and cryogenic temperatures were tested. Both strength and plasticity of alloy were significantly increased at reducing test temperatures from 20 to –196 ^оC. Also when testing temperature reduced the difference between tensile strength and yield strength was increased. High “cryogenic” characteristics of new alloy were confirmed by the low level of sensitivity to stress concentrator (σ_в^н /σ_в) which is 1.0–0.9. Tensile strength and yield strength of the alloy 1565ч are at 20% higher than for similar alloys which are recommended for use at cryogenic temperatures (for example, alloys AMg5 and 5083) in the whole range of investigated temperatures. According to the analysis of structure the sample fracture was plastic at all temperatures. Due to combination of high strength and plasticity under room and low temperatures, and low sensitivity to stress concentrator, new alloy 1565ч can be considered as a multifunctional structural material, suitable for the production of various types of products and constructions, working in a wide range of temperatures, particularly for welded tank for storage and transportation of liquefied natural gas (LNG).

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