Effect of T6I6 and its modified processes on mechanical properties of novel high strength Al-Li alloy-2A97
(1.辽宁省沈阳市东北大学材料与冶金学院
2.北京市北京航空材料研究所铝镁研究室
3.Beijing Institute of Aeronautical Materials, Beijing 100095, China
4.School of Materials and Metallurgy, Northeastern University, Shenyang 110004, China)
2.北京市北京航空材料研究所铝镁研究室
3.Beijing Institute of Aeronautical Materials, Beijing 100095, China
4.School of Materials and Metallurgy, Northeastern University, Shenyang 110004, China)
Abstract: Based on a novel high strength Al-Cu-Li-X alloy-2A97, the effect of T6I6 and its modified processes on the properties investigated by SEM and tensile test. The results show that when the alloy is heat treated by triple ageing, with secondary low temperature ageing at 80 ℃ after initial ageing at 155 and 150 ℃, and final re-ageing at 135 and 165 ℃, the tensile properties are close to the peak level of aged alloy in T6 temper. The addition of plastic deformation after and prior to secondary ageing favor the T1(Al2CuLi) and δ′(Al3Li) precipitation during final re-ageing at 135 and 165 ℃ corresponding to triple ageing, so the Al-Li alloy displays higher strength for the modified processes of T6I6. The microstructures consist of δ′, T1 and θ″/θ′ (Al2Cu) phase for single and triple aged alloy, the number density and volume fraction of δ′ phase increase for T6I6 and its modified processes correspond to single ageing.
Key words: Al-Cu-Li-X alloy; 2A97; T6I6; triple ageing; microstructure