Initially, 7050 Alloy was an aircraft aluminum alloy studied by Alcoa with the assistance of naval aviation force and air compression material laboratory for the purpose of improving strength, hardenability and stress corrosion crack resistance. This alloy is different from the past 7x series alloys. Zr is added instead of Cr in order to improve the hardenability. The ratio of Cu / Mg is greater than 0.85. In particular, the strength is improved by increasing the Cu content. At the same time, the stress corrosion crack resistance in the thickness direction is also improved.
The hardenability of 7050 Alloy is better than that of 7075. Its characteristic is that high strength can be obtained even if it is cooled slowly from the solution heat treatment temperature.
Chalco aluminum manufactured
7050 T7451 t76511 aluminum extrusion for aircraft, and its various properties were compared and studied with those of 7075 alloy. The following conclusions were drawn:
(1) Under various conditions, the static strength of 7050 Alloy is 10 N / mm2 - 20 N / mm2o higher than that of 7075 alloy
(2) In terms of fracture toughness, 7050 Alloy is slightly inferior to 7075 alloy, and the superiority of 7050 Alloy mentioned before can not be determined. Further research is needed on this point in the future.
(3) The fatigue crack growth rate of
7050 T7451 t76511 aluminum extrusion also tends to increase in a small range, and the fatigue crack growth rate of 7075 alloy in L-T direction is particularly large. In addition, the fatigue strength (b) of 7050 Alloy is 20 N / mm2o higher than that of 7075 alloy
(4) In terms of stress corrosion crack resistance, 7050 and 7075 alloys have almost the same level.
(5) The hardenability of
7050 Alloy with Zr is better than that of 7075 alloy with CR.
(6) Based on the above results, the strength and fatigue strength of 7050 Alloy are 10 N / mm2 higher than that of 7075 alloy~
20 N / mm2 and good hardenability, so it is a high-strength alloy suitable for thick plate and large die forgings.
