Effects of pre-stretch on microstructure, mechanical properties and corrosion resistance of 2A14 aluminum alloy
(1. Powder Metallurgy Research Institute, Central South University, Changsha 410083, China;
2. State Key Laboratory of Light Weight and High Strength Structural Materials, Central South University, Changsha 410083, China;
3. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
4. Light Alloy Research Institute, Central South University, Changsha 410083, China;
5. Collaborative Innovation Center of Advance Nonferrous Structural Materials and Manufacturing, Central South University, Changsha 410083, China)
2. State Key Laboratory of Light Weight and High Strength Structural Materials, Central South University, Changsha 410083, China;
3. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
4. Light Alloy Research Institute, Central South University, Changsha 410083, China;
5. Collaborative Innovation Center of Advance Nonferrous Structural Materials and Manufacturing, Central South University, Changsha 410083, China)
Abstract: The microstructure, mechanical properties and corrosion behaviors of the peak-aged 2A14 aluminum alloys subjected to pre-stretch prior to artificial aging were investigated. The results indicate that the hardness and strength of the peak-aged alloy can be greatly enhanced via introducing pre-stretch due to the formation of dense and finer θ′ precipitates with dispersed distribution in alloy matrix. Pre-stretch prior to peak aging evidently enhances the peak aging hardness and shortens the peak aging time of the alloy. A pre-stretching degree of 7.5% leads to a distinct inhomogeneous distribution of θ′ phase, which decreases the ultimate tensile strength. As pre-stretching degree increases, the plasticity, impact toughness and exfoliation corrosion (EXCO) resistance of the peak-aged alloy all gradually decrease, but its resistance to intergranular corrosion (IGC) increases and then decreases.
Key words: 2A14 aluminum alloy; pre-stretch; microstructure; mechanical properties; corrosion resistance