Effect of the Zn/Mg Ratio on Microstructures, Mechanical Properties and Corrosion Performances of Al-Zn-Mg Alloys
Abstract
:1. Introduction
2. Experimental
3. Results and Discussions
3.1. Effect of the Zn/Mg Ratios on Microstructures
3.2. Effect of the Zn/Mg Ratios on Mechanical Properties
3.3. Effect of Zn/Mg Ratios on Corrosion Performances
4. Conclusions
- With the decrease of the Zn/Mg ratio, the recrystallization proportion decreased, the number fraction of the second phase decreased and the size of the η’ phase in grain interior significantly decreased. While the number density of η’ phase in grain interior increased and the gap between the grain boundary precipitates increased with the decrease of Zn/Mg ratio.
- The tensile strength and yield strength are increased by 34.1% and 47.4%, respectively, with the Zn/Mg ratio decreased from 11.4 to 6.1. The elongation of alloys with the Zn/Mg ratio of 11.4, 8.1 and 6.1 is 18.4%, 17.6% and 18.9%, respectively. Experimental yield strength of alloy with the Zn/Mg ratio of 8.1 was higher than theoretical, while on alloys with the Zn/Mg ratio of 11.4 and 6.1 occurred the opposite. Calculating results indicated that the enhancement of strength mainly contributed from the solid-solution strengthening, grain-boundary strengthening and precipitation strengthening.
- The intergranular corrosion degree is greatly relieved with the decrease of the Zn/Mg ratio. The stress corrosion sensitivity index is 0.031, 0.015 and 0.007 for the Zn/Mg ratio with 11.4, 8.1 and 6.1, respectively. The stress corrosion resistance of alloys improved with the decrease of the Zn/Mg ratio.
Author Contributions
Funding
Conflicts of Interest
References
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Alloys | Zn/Mg | Zn and Mg | Zn | Mg | Cu | Mn | Cr | Ti | Zr | Fe | Si | Al |
---|---|---|---|---|---|---|---|---|---|---|---|---|
1# | 11.4 | 6.57 | 6.04 | 0.53 | 0.17 | 0.25 | 0.12 | 0.08 | 0.20 | 0.15 | 0.06 | bal. |
2# | 8.1 | 6.57 | 5.85 | 0.72 | 0.16 | 0.23 | 0.15 | 0.07 | 0.17 | 0.15 | 0.06 | bal. |
3# | 6.1 | 6.61 | 5.68 | 0.93 | 0.16 | 0.26 | 0.14 | 0.08 | 0.19 | 0.14 | 0.07 | bal. |
Zn/Mg Ratios | δ (μm) | D (μm) | (%) | (MPa) |
---|---|---|---|---|
11.4 | 2.5 | 3.9 | 64 | 4.9 |
8.1 | 1.2 | 3.2 | 53 | 8.9 |
6.1 | 0.8 | 3.7 | 44.9 | 13.0 |
Zn/Mg Ratios | Zn | Mg | Cu | (MPa) |
---|---|---|---|---|
11.4 | 6.04 | 0.53 | 0.17 | 27.2 |
8.1 | 5.85 | 0.72 | 0.16 | 29.8 |
6.1 | 5.68 | 0.93 | 0.16 | 32.6 |
Zn/Mg Ratios | d (nm) | Nv (μm3) | (MPa) |
---|---|---|---|
11.4 | 4.3 | 6.65 × 104 | 68.56 |
8.1 | 4.0 | 8.79 × 104 | 74.12 |
6.1 | 3.7 | 1.18 × 105 | 80.30 |
Alloy | Corrosive Environment | Rm (MPa) | Elongation (%) | ISSRT |
---|---|---|---|---|
1# | Air | 332.58 | 18.8 | 0.031 |
3.5 wt% NaCl | 324.61 | 17.9 | ||
2# | Air | 395.73 | 19.2 | 0.015 |
3.5 wt% NaCl | 391.22 | 18.7 | ||
3# | Air | 429.67 | 19.5 | 0.007 |
3.5 wt% NaCl | 427.57 | 19.2 |
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Jiang, K.; Lan, Y.; Pan, Q.; Deng, Y. Effect of the Zn/Mg Ratio on Microstructures, Mechanical Properties and Corrosion Performances of Al-Zn-Mg Alloys. Materials 2020, 13, 3299. https://0-doi-org.brum.beds.ac.uk/10.3390/ma13153299
Jiang K, Lan Y, Pan Q, Deng Y. Effect of the Zn/Mg Ratio on Microstructures, Mechanical Properties and Corrosion Performances of Al-Zn-Mg Alloys. Materials. 2020; 13(15):3299. https://0-doi-org.brum.beds.ac.uk/10.3390/ma13153299
Chicago/Turabian StyleJiang, Keda, Yanquan Lan, Qinglin Pan, and Yunlai Deng. 2020. "Effect of the Zn/Mg Ratio on Microstructures, Mechanical Properties and Corrosion Performances of Al-Zn-Mg Alloys" Materials 13, no. 15: 3299. https://0-doi-org.brum.beds.ac.uk/10.3390/ma13153299