Significantly enhanced fatigue resistance and mechanisms of hypoeutectic Al-Si composite calibrated using trace in-situ nanocrystals
Abstract
Fatigue resistance under extreme stress conditions is an important indicator to evaluate industrial application potential of Al-Si-Mg alloys, but their fatigue resistance is inherently weakened by large grain size, long-needle Si phases and coarse precipitates. This work reports significantly optimized microstructure configuration and fatigue resistance of hypoeutectic Al-Si composite optimized by the nanocrystallization products of a NiNbTi metallic glass. It was proved the in-situ NiTi (B2) nanocrystals can serve as the heterogeneous nucleation sites of -Al and -Mg2Si and the growth retarder of eutectic Si. Particularly, the optimized composite exhibited nearly 5 times and 6 times longer fatigue life than the unoptimized alloy at 120 MPa (60 Hz) and 240 MPa (20 Hz), respectively. The fatigue strength (N = 107) was increased by 21.7 % and 25.9 % at 60 Hz and 20 Hz, respectively. The -Al refinement enhanced the resistance to fatigue crack initiation. The refinement and spheroidization of eutectic Si phases reduced stress concentration. Also, the austenite-martensite phase transformation of NiTi afforded more energy for precipitation. Refined -Mg2Si and '' phases were facilitated to interact with dislocations, improving the resistance to dislocation slip during cyclic strain through the dislocation shearing effect. This work provides a theoretical basis for the future development of Al-Si alloys and composites with excellent fatigue resistance for expanding their industrial application scope.
RAS ID
64703
Document Type
Journal Article
Date of Publication
2-15-2024
Volume
271
Funding Information
National Natural Science Foundation of China / Science and Technology Development Program of Jilin Province, China / Exploration Foundation of State Key Laboratory of Automotive Simulation and Control / Undergraduate Innovation Fund of Jilin University, China
School
School of Engineering
Copyright
subscription content
Publisher
Elsevier
Recommended Citation
Liu, T., Zhu, L., Yang, H., Cui, H., Meng, J., Qiu, F., Dong, B., Shu, S., Jiang, Q., & Zhang, L. (2024). Significantly enhanced fatigue resistance and mechanisms of hypoeutectic Al-Si composite calibrated using trace in-situ nanocrystals. DOI: https://doi.org/10.1016/j.compositesb.2023.111138
Comments
Liu, T. S., Zhu, L., Yang, H. Y., Cui, H. Y., Meng, J., Qiu, F., . . . Zhang, L. C. (2024). Significantly enhanced fatigue resistance and mechanisms of hypoeutectic Al-Si composite calibrated using trace in-situ nanocrystals. Composites Part B: Engineering, 271, article 111138. https://doi.org/10.1016/j.compositesb.2023.111138