Growth Mechanism of Eutectic Si in Super-Gravity Solidified Al-Si Alloy during Annealing
Abstract
:1. Introduction
2. Experimental Process
3. Results
3.1. Microstructure
3.2. Mechanical Behavior
3.3. Fractography
4. Discussion
4.1. Refining Mechanism of Eutectic Si during Super-Gravity Solidification
4.2. Growth Mechanism of Si
5. Conclusions
- (1)
- With an increase in annealing time, growth and coarsening of metastable eutectic Si could be observed. Interestingly, coalescence of rod-like Si could be observed after annealing, forming several long, needle-like Si particles with dozens of microns. In addition, the formation of precipitated Si was detected in α-Al, which grew during the annealing process.
- (2)
- The yield (~121.5 MPa) and tensile strength (~235.9 MPa) of the A-0.25 sample were ~9.8% and ~5.1% higher than those of the A-0 sample, respectively. Slight increases in the yield strength and tensile strength could be observed in the A-0.25 sample, which can be ascribed to the formation of precipitated Si of limited size during the early stage of annealing. A decrease in tensile stress was observed with further extension of the annealing time.
- (3)
- Heat exposure had an influence on the size and distribution of eutectic Si in the super-gravity solidified bulks. The mutual diffusion of Al and Si during annealing led to the coarsening and coalescence of the eutectic Si, as well as the coarsening of precipitated Si.
Author Contributions
Funding
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Annealing Time (h) | Yield Strength (MPa) | Tensile Strength (MPa) | Elongation (%) | Length (μM) | Width (μM) | Hardness (HV) |
---|---|---|---|---|---|---|
0 h | 110.7 | 224.4 | 11.9 | 0.47 | 0.25 | 86.7 |
0.25 h | 121.5 | 235.9 | 12.2 | 1.21 | 0.34 | 69.3 |
0.5 h | 95.6 | 194.1 | 9.8 | 1.46 | 0.43 | 64.3 |
1 h | 105.4 | 203.5 | 9.1 | 1.82 | 0.40 | 68.7 |
2 h | 98.9 | 199.7 | 13.9 | 1.96 | 0.43 | 67.0 |
4 h | 89.9 | 179.3 | 12.8 | 2.17 | 0.56 | 64.5 |
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Lu, Y.; Wu, C.; Wu, H.; Wang, J.; Su, Y.; Gan, Z.; Liu, J. Growth Mechanism of Eutectic Si in Super-Gravity Solidified Al-Si Alloy during Annealing. Crystals 2023, 13, 684. https://doi.org/10.3390/cryst13040684
Lu Y, Wu C, Wu H, Wang J, Su Y, Gan Z, Liu J. Growth Mechanism of Eutectic Si in Super-Gravity Solidified Al-Si Alloy during Annealing. Crystals. 2023; 13(4):684. https://doi.org/10.3390/cryst13040684
Chicago/Turabian StyleLu, Yuehui, Chuandong Wu, Hao Wu, Jiamin Wang, Yin Su, Zhanghua Gan, and Jing Liu. 2023. "Growth Mechanism of Eutectic Si in Super-Gravity Solidified Al-Si Alloy during Annealing" Crystals 13, no. 4: 684. https://doi.org/10.3390/cryst13040684
APA StyleLu, Y., Wu, C., Wu, H., Wang, J., Su, Y., Gan, Z., & Liu, J. (2023). Growth Mechanism of Eutectic Si in Super-Gravity Solidified Al-Si Alloy during Annealing. Crystals, 13(4), 684. https://doi.org/10.3390/cryst13040684