Influence of multi-stage aging heat treatment on precipitation microstructure and corrosion resistance of 7056 aluminum alloy
The influence of different multi-stage aging heat treatment on microstructure and corrosion resistance of 7056 alloy was investigated by the measurements of transmission electron microscope(TEM), scanning electron microscope(SEM),mechanical properties and electrical conductivity, exfoliation corrosi...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | zho |
| Published: |
Journal of Materials Engineering
2019-06-01
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| Series: | Journal of Materials Engineering |
| Subjects: | |
| Online Access: | http://jme.biam.ac.cn/CN/Y2019/V47/I6/136 |
| Summary: | The influence of different multi-stage aging heat treatment on microstructure and corrosion resistance of 7056 alloy was investigated by the measurements of transmission electron microscope(TEM), scanning electron microscope(SEM),mechanical properties and electrical conductivity, exfoliation corrosion, slow strain rate testing(SSRT), Tafel cyclic polarization. The results show that after over-aging and re-aging heat treatment, the solute atoms precipitate again, and the volume fraction of the precipitate in the matrix increases, the grain boundary precipitates coarsen and become discontinuous, the precipitate-free zone becomes wider. Compared with 120℃/24h pre-aging,120℃/6h has advantage in terms of dissolution of finer precipitates and the growth of large coarse phase. Re-aging heat treatment can improve the strength and conductivity of over-aging alloys;compared with peak aging and retrogression and re-aging, the loss of tensile strength of the alloy is not significant, while the conductivity increases obviously. After over-aging and re-aging heat treatment, continuous anodic dissolution is avoided effectively, and the exfoliation corrosion resistance and stress corrosion cracking is enhanced. |
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| ISSN: | 1001-4381 1001-4381 |