Characterization of Microstructure, Weld Heat Input, and Mechanical Properties of Mg–Al–Zn Alloy GTA Weldments
Abstract
:1. Introduction
2. Materials and Methods
3. Results and Discussion
3.1. Base Metal Microstructure
3.2. Weld Zone Macrostructure
3.3. Weld Zone Microstructure
3.4. Thermal Profile
3.5. Hardness
3.6. Tensile Properties
4. Conclusions
- The GTA welding technique produced sound AZ31 Mg weldments, without any defects, such as solidification cracking or liquation cracking, except in a few scattered pores;
- The microstructural examination of the fusion zone reveals that the average grain size of the equiaxed zone decreases with increasing welding speed;
- The welds prepared with high welding speed (low heat input) exhibit improved strength and ductility compared with low welding speeds, due to finer equiaxed dendritic grains;
- The welds prepared with low welding speed exhibit a reduction in strength and ductility compared with high welding speed. This is attributed to the coarse columnar dendrites present in the fusion zone. However, the AZ31 base metal exhibits good strength and ductility values compared with all welded joints, due to the work hardening effect of the wrought base metal;
- Increased welding speed lowers the heat input and increases the cooling rates, thereby reducing the temperature gradient G, and increasing constitutional supercooling, to allow more nuclei to survive and grow into fine equiaxed dendritic grains in the fusion zone.
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Al | Mn | Zn | Mg |
---|---|---|---|
2.75 | 0.31 | 0.80 | Balance |
Alternating Current GTA Welds | |
---|---|
Alternating current amplitude | 115 A |
Arc voltage | 11 V |
Travel speed | 3, 4, 5 mm/s |
Frequency | 50 Hz |
Heat input | 421, 316, 253 J/mm |
Condition | Welding Speed (mm/s) | Yield Strength (YS), MPa | Ultimate Tensile Strength (UTS), MPa | Elongation (%) |
---|---|---|---|---|
AZ31 base metal | - | 210 ± 5 | 255 ± 8 | 17 ± 1 |
AZ31 GTA weld | 3 | 120 ± 5 | 165 ± 7 | 5 ± 1 |
AZ31 GTA weld | 4 | 140 ± 9 | 198 ± 7 | 6.5 ± 1 |
AZ31 GTA weld | 5 | 160 ± 6 | 215 ± 4 | 8 ± 0.5 |
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Babu, N.K.; Talari, M.K.; Srirangam, P.; AlFaify, A.Y.; Rehman, A.U. Characterization of Microstructure, Weld Heat Input, and Mechanical Properties of Mg–Al–Zn Alloy GTA Weldments. Appl. Sci. 2022, 12, 4417. https://doi.org/10.3390/app12094417
Babu NK, Talari MK, Srirangam P, AlFaify AY, Rehman AU. Characterization of Microstructure, Weld Heat Input, and Mechanical Properties of Mg–Al–Zn Alloy GTA Weldments. Applied Sciences. 2022; 12(9):4417. https://doi.org/10.3390/app12094417
Chicago/Turabian StyleBabu, Nagumothu Kishore, Mahesh Kumar Talari, Prakash Srirangam, Abdullah Yahia AlFaify, and Ateekh Ur Rehman. 2022. "Characterization of Microstructure, Weld Heat Input, and Mechanical Properties of Mg–Al–Zn Alloy GTA Weldments" Applied Sciences 12, no. 9: 4417. https://doi.org/10.3390/app12094417
APA StyleBabu, N. K., Talari, M. K., Srirangam, P., AlFaify, A. Y., & Rehman, A. U. (2022). Characterization of Microstructure, Weld Heat Input, and Mechanical Properties of Mg–Al–Zn Alloy GTA Weldments. Applied Sciences, 12(9), 4417. https://doi.org/10.3390/app12094417