| 2xxx series aluminum alloys are high strength aluminum alloys,which are widely used in aerospace industry and are one of the most important new generation aerospace materials.They generally have the advantages of low density,high modulus of elasticity,high specific strength,low plane anisotropy and low fatigue crack growth rate.They are one of the most ideal lightweight structural materials.In this paper,2198 and 2024 alloy samples were selected as the research objects,and the microstructure of T1,S and T phases in aging process.In the first half of the project,the original samples were heated by solid solution and aging treatment,and the hardness test was used to explore the strengthening effect of aluminum alloy after solid solution,as well as the regularity of the strengthening effect changing with aging time.In the second half of the project,TEM samples were prepared by twin-jet and were observed under TEM to explore their growth mechanism.T1 phase is the main strengthening phase in the aging process of 2198Al-Li alloy.With the increasing of aging time,the number and size of T1phase increased.And multi-layered structure appeared,and its microstructure may change.The main strengthening phases of 2024 alloy are S phase and T phase.S phase is aging phase.It has metastable phases such as GPB zone,S"phase,S?,etc.They will be formed before fully growing up.Different metastable phases of S phase may occur at the same time.T phase usually appears in homogenization heat treatment and its structure remains stable during aging process. |
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