Aluminium/Steel Joints with Dissimilar Thicknesses: Enhancement of UTS and Ductility Through Making an S-Shaped Interface and a Mixed-Mode Fracture
Abstract
1. Introduction
2. Experimental Procedure
2.1. Joint Manufacturing
2.2. SEM/EDS Analysis
- U—upper part of the interface;
- M1, M2, and M3—middle part of the interface;
- L—lower tip of the interface;
- B—bottom part of the interface.
2.3. Mechanical Tests and Fractography
2.4. TEM and EBSD Analyses
3. Results and Discussion
3.1. Joint Geometry and Interface Microstructure
3.2. IMC Layer Thicknesses
3.3. Microhardness Analysis
3.4. Mechanical Properties and Fracture Behaviour
4. Conclusions
- The process produced a unique S-shaped interface between aluminium and steel, facilitated by the use of a run-on plate and support plates.
- This S-shaped interface enhanced the joint’s ultimate tensile strength (UTS) by 150% and improved its ductility. The curvature of the interface prevented it from being entirely perpendicular to the loading direction, contributing to better mechanical performance.
- According to EBSD results, the stir zone of Al consists of fine grains (below 1 µm) with a B-fibre texture, indicating a strong shear deformation and dynamic recrystallization.
- According to TEM images, St was not in the stir zone due to the absence of recrystallized and equiaxed grains. St in the vicinity of the interface is deformed plastically, causing the grains to be elongated in this region, with some evidence of partial recrystallization.
- The weld exhibited a varying intermetallic compound (IMC) microstructure along the joint interface, with a gradient in IMC layer thickness. The thickness decreased from 4 µm at the top of the interface to 2.5 µm in the middle and less than 0.1 µm at the bottom. This gradient corresponded to the peak temperatures experienced during the welding process along the interface.
- Tensile testing revealed that failure occurred through the IMC layers in a brittle manner at the middle section, where the interface was perpendicular to the loading direction. Conversely, at the curved sections of the interface (top and bottom), failure was ductile, leaving aluminium remnants on the steel surface.
- IMC thickness plays a critical role in lowering the joint strength when the interface is loaded in tension. However, the IMC thickness is not decisive in the joint strength when the interface is loaded in shear.
Author Contributions
Funding
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Elements (Wt%) | |||||||||
---|---|---|---|---|---|---|---|---|---|
Ti | Zn | Mg | Cu | Si | Mn | C | Al | Fe | |
- | - | - | - | 0.4≥ | 0.35–0.65 | 0.17–0.2 | - | Bal. | St37 |
0.03 | 0.05 | 0.05 | 0.05 | 0.25 | 0.05 | - | Bal. | 0.4 | AA1050 |
Mechanical Properties | |||||||||
Hardness (VH) | Yield Strength (MPa) | Tensile Strength (MPa) | |||||||
120 | 300 | 370 | St37 | ||||||
41 | 85 | 100–135 | AA1050 |
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Teixeira, T.O.G.; Beygi, R.; Carbas, R.J.C.; Marques, E.A.S.; Bolhasani Hesari, M.; Kasaei, M.M.; da Silva, L.F.M. Aluminium/Steel Joints with Dissimilar Thicknesses: Enhancement of UTS and Ductility Through Making an S-Shaped Interface and a Mixed-Mode Fracture. J. Manuf. Mater. Process. 2025, 9, 120. https://doi.org/10.3390/jmmp9040120
Teixeira TOG, Beygi R, Carbas RJC, Marques EAS, Bolhasani Hesari M, Kasaei MM, da Silva LFM. Aluminium/Steel Joints with Dissimilar Thicknesses: Enhancement of UTS and Ductility Through Making an S-Shaped Interface and a Mixed-Mode Fracture. Journal of Manufacturing and Materials Processing. 2025; 9(4):120. https://doi.org/10.3390/jmmp9040120
Chicago/Turabian StyleTeixeira, Tiago Oliveira Gonçalves, Reza Beygi, Ricardo João Camilo Carbas, Eduardo Andre Sousa Marques, Masih Bolhasani Hesari, Mohammad Mehdi Kasaei, and Lucas Filipe Martins da Silva. 2025. "Aluminium/Steel Joints with Dissimilar Thicknesses: Enhancement of UTS and Ductility Through Making an S-Shaped Interface and a Mixed-Mode Fracture" Journal of Manufacturing and Materials Processing 9, no. 4: 120. https://doi.org/10.3390/jmmp9040120
APA StyleTeixeira, T. O. G., Beygi, R., Carbas, R. J. C., Marques, E. A. S., Bolhasani Hesari, M., Kasaei, M. M., & da Silva, L. F. M. (2025). Aluminium/Steel Joints with Dissimilar Thicknesses: Enhancement of UTS and Ductility Through Making an S-Shaped Interface and a Mixed-Mode Fracture. Journal of Manufacturing and Materials Processing, 9(4), 120. https://doi.org/10.3390/jmmp9040120