Low Temperature Superplasticity of High-Strength Ultrafine-Grained Al 7050 alloy

5th International Conference Recent Trends in Structural Materials

Bobruk, E.V.^1,2 ; Murashkin, M.Yu.^1,2 ; Lomakin, I.V.^2 ; Kazykhanov, V.U.^1 ; Valiev, R.Z.^1,2

Ufa State Aviation Technical University, 12 K. Marx str., Ufa

450008, Russia^1

Saint Petersburg State University, Universitetskiy Prospekt 28, Peterhof, St. Petersburg

198504, Russia^2

关键词: Alloy structures;    Elongation to failure;    Increasing temperatures;    Low temperature superplasticity;    Superplastic behavior;    Ultra fine grain;    Ultra-fine grained ( UFG);    Ultra-fine-grained;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/461/1/012090/pdf
DOI  :  10.1088/1757-899X/461/1/012090

来源: IOP

【 摘 要 】

Ultrafine-grained (UFG) Al 7050 alloy of the 7xxx series demonstrates very high strength at room temperature with UTS=845 MPa and hardness Hv=255, which considerably exceeds the value after conventional heat treatment T73, i.e. Hv=165. It is also revealed that with increasing temperature the alloy exhibits rather high ductility with elongation to failure δ=170% at 120 °C and strain rate of 5×104 s-1 and typical superplastic behavior with δ=480% and δ=690% at temperatures 170 °C and 200 °C correspondingly. Such values of superplasticity (SP) temperature are considerably lower than that typical of this alloy with micron-sized grains (TSP=450-500 °C). Such reduction in superplasticity temperature made it possible to preserve ultrafine grains in the alloy structure and provide its high-strength state after SP straining.