Effect Of Fly Ash Content on Microstructure and Mechanical Properties of Aluminium Matrix Composite Processed by Cooling Slope Casting
DOI:
https://doi.org/10.24237/djes.2026.19109Keywords:
A356, Fly ash, Cooling slope casting, T6 heat treatment, Taguchi method,Abstract
Metal matrix composites (MMCs) have emerged as promising materials for aerospace and automotive applications due to their enhanced mechanical performance. Among various reinforcements, fly ash has gained increasing attention for aluminium-based MMCs because of its low cost, low density, and favourable mechanical characteristics. However, the influence of fly ash content on the microstructural evolution and mechanical behaviour of aluminium MMCs fabricated via cooling slope casting remains insufficiently explored. In this study, aluminium MMCs reinforced with 4, 8, and 12 wt.% fly ash were produced using cooling slope casting under different pouring temperatures and slope lengths, followed by T6 heat treatment. Mechanical properties were evaluated through tensile and hardness testing, while microstructural characterization was performed using optical microscopy, FESEM with EDX, and XRD analysis. Quantitative image analysis was employed to determine the globule size and shape factor of the primary α-Al phase. The results demonstrate that increasing fly ash content promotes grain refinement, reduces globule size, and enhances globularity, indicating improved microstructural stability after heat treatment. These microstructural improvements, together with precipitation hardening and more effective load transfer, lead to significant mechanical strengthening, with yield strength, ultimate tensile strength, and hardness increasing by 43%, 25%, and 29%, , while elongation is maintained with a modest improvement of approximately 4%. Furthermore, the lower density of fly ash contributes to overall weight reduction, making these composites attractive for lightweight structural applications. The findings highlight the potential of fly ash-reinforced aluminium MMCs as cost-effective, high-performance materials for engineering applications.
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[1] A. Kar, A. Sharma, and S. Kumar, “A Critical Review on Recent Advancements in Aluminium-Based Metal Matrix Composites,” May 01, 2024, Multidisciplinary Digital Publishing Institute (MDPI). doi: 10.3390/cryst14050412.
[2] A. T. Oyewo, O. O. Oluwole, O. O. Ajide, T. E. Omoniyi, and M. Hussain, “A summary of current advancements in hybrid composites based on aluminium matrix in aerospace applications,” Hybrid Advances, vol. 5, p. 100117, Apr. 2024, doi: 10.1016/j.hybadv.2023.100117.
[3] X. Wu and W. Zhang, “A review on aluminum matrix composites’ characteristics and applications for automotive sector,” Oct. 30, 2024, Elsevier Ltd. doi: 10.1016/j.heliyon.2024.e38576.
[4] H. S. Bang, H. I. Kwon, S. B. Chung, D. U. Kim, and M. S. Kim, “Experimental Investigation and Numerical Simulation of the Fluidity of A356 Aluminum Alloy,” Metals (Basel)., vol. 12, no. 11, Nov. 2022, doi: 10.3390/met12111986.
[5] S. H. Budapanahalli et al., “A Tribological Study on the Effect of Reinforcing SiC and Al2O3 in Al7075: Applications for Spur Gears,” Metals (Basel)., vol. 12, no. 6, Jun. 2022, doi: 10.3390/met12061028.
[6] M. Wang, D. Chen, H. Wang, and W. Gao, “A review on fly ash high-value synthesis utilization and its prospect,” Mar. 01, 2024, Elsevier B.V. doi: 10.1016/j.gerr.2024.100062.
[7] B. K. Shukla, A. Gupta, S. Gowda, and Y. Srivastav, “Constructing a greener future: A comprehensive review on the sustainable use of fly ash in the construction industry and beyond,” in Materials Today: Proceedings, Elsevier Ltd, 2023, pp. 257–264. doi: 10.1016/j.matpr.2023.07.179.
[8] A. K. Kasar, N. Gupta, P. K. Rohatgi, and P. L. Menezes, “A Brief Review of Fly Ash as Reinforcement for Composites with Improved Mechanical and Tribological Properties,” Jun. 01, 2020, Springer. doi: 10.1007/s11837-020-04170-z.
[9] P. Satishkumar, A. J. Infant Jegan Rakesh, R. Meenakshi, and C. Saravana Murthi, “Characterization, mechanical and wear properties of Al6061/Sicp/fly ashp composites by stir casting technique,” in Materials Today: Proceedings, Elsevier Ltd, 2020, pp. 2687–2694. doi: 10.1016/j.matpr.2020.08.530.
[10] U. Devadiga, S. Kumar Shetty, and P. Fernandes, “Effect of multiwalled carbon nanotubes on densification behaviour of multiwalled carbon nanotube and fly ash reinforced aluminium composites,” in Materials Today: Proceedings, Elsevier Ltd, 2021, pp. 2602–2606. doi: 10.1016/j.matpr.2021.02.263.
[11] M. Sanju, M. Saravanan, G. Gokul Krishna, and S. Kumaran, “ScienceDirect An Investigation of Wear Behavior on AA7075 MMC reinforced with CNT and Fly ash Composites,” 2019. [Online]. Available: www.sciencedirect.com
[12] N. Vinoth Babu, M. Siva, M. Subramanian, R. Elakkiyadasan, and P. Manoj Kumar, “Investigation of mechanical characteristics of SiC and flyash particle reinforced aluminium matrix composites,” in Materials Today: Proceedings, Elsevier Ltd, Jan. 2022, pp. 4316–4321. doi: 10.1016/j.matpr.2022.04.829.
[13] P. Chechi, S. K. Maurya, R. Prasad, and A. Manna, “Microstructural and mechanical characterization of stir cast Al-SiC/Flyash/Graphite hybrid metal matrix composite,” in Materials Today: Proceedings, Elsevier Ltd, Jan. 2022, pp. 637–642. doi: 10.1016/j.matpr.2022.05.150.
[14] P. Das, “Microstructure Evolution During Rheoprocessing of A356 Al Alloy Using Cooling Slope,” International Journal of Metalcasting, vol. 17, no. 3, pp. 1982–2001, Jul. 2023, doi: 10.1007/s40962-022-00908-4.
[15] M. Jahanbakhshi, S. Nourouzi, R. Naseri, and K. Esfandiari, “Investigation of Simultaneous Effects of Cooling Slope Casting and Mold Vibration on Mechanical and Microstructural Properties of A356 Aluminum Alloy,” Metals and Materials International, vol. 28, no. 6, pp. 1508–1516, Jun. 2022, doi: 10.1007/s12540-021-01056-w.
[16] A. K. Yadav, V. Kumar, Ankit, and S. Mohan, “Microstructure and Mechanical Properties of an In Situ Al 356-Mg2Si-TiB2 Hybrid Composite Prepared by Stir and Cooling Slope Casting,” International Journal of Metalcasting, vol. 17, no. 2, pp. 740–752, Apr. 2023, doi: 10.1007/s40962-022-00804-x.
[17] M. S. SALLEH et al., “T6 Heat Treatment Optimization of Thixoformed LM4 Aluminium Alloy using Response Surface Methodology,” Malaysian Journal on Composites Science and Manufacturing, vol. 3, no. 1, pp. 1–13, Sep. 2020, doi: 10.37934/mjcsm.3.1.113.
[18] G. N. Lokesh, K. P. Prashanth, G. P. Prasad, and B. K. Venkatesha, “Mechanical and microstructure evaluation of stir cast Al-4.5%Cu alloy reinforced fly ash/boron carbide hybrid metal matrix composites,” Mater. Today Proc., vol. 54, pp. 486–491, Jan. 2022, doi: 10.1016/j.matpr.2021.11.131.
[19] N. Vinoth Babu, M. Siva, M. Subramanian, R. Elakkiyadasan, and P. Manoj Kumar, “Investigation of mechanical characteristics of SiC and flyash particle reinforced aluminium matrix composites,” in Materials Today: Proceedings, Elsevier Ltd, Jan. 2022, pp. 4316–4321. doi: 10.1016/j.matpr.2022.04.829.
[20] S. H. Juang and C. F. Li, “Influence of Different Addition Ratios of Fly Ash on Mechanical Properties of ADC10 Aluminum Matrix Composites,” Metals (Basel)., vol. 12, no. 4, Apr. 2022, doi: 10.3390/met12040653.
[21] H. Hanizam, M. S. Salleh, M. Z. Omar, A. B. Sulong3, S. H. Yahaya, and N. Siswanto, “Effect of Magnesium Surfactant on Wettability of Carbon Nanotube in A356 Alloy Composite,” Journal of Advanced Manufacturing Technology (JAMT), 2019.
[22] P. Mohapatra and N. K. Kund, “Impact of ultrasonic power on liquid fraction, microstructure and physical characteristics of A356 alloy molded through cooling slope,” J. Cent. South Univ., vol. 29, no. 4, pp. 1098–1106, Apr. 2022, doi: 10.1007/s11771-022-4942-8.
[23] N. F. B. W. Anuar et al., “INVESTIGATION OF T6 HEAT TREATMENT ON DRY SLIDING WEAR BEHAVIOUR OF THIXOFORMED A356 COMPOSITE REINFORCED WITH GRAPHENE,” Journal of Advanced Manufacturing Technology (JAMT), vol. 18, no. 2, Aug. 2024.
[24] R. Umunakwe, I. J. Umunakwe, U. S. Nwigwe, W. U. Eze, and A. Oyetunji, “Review on properties of hybrid aluminum–ceramics/fly ash composites,” 2020, AIMS Press. doi: 10.3934/matersci.2020.6.859.
[25] A. M. Razzaq, D. L. Majid, U. M. Basheer, and H. S. S. Aljibori, “Research summary on the processing, mechanical and tribological properties of aluminium matrix composites as effected by fly ash reinforcement,” Crystals (Basel)., vol. 11, no. 10, Oct. 2021, doi: 10.3390/cryst11101212.
[26] M. Muslić, V. Rede, V. Maksimović, and D. Ćorić, “Hardness and Microstructural Characterization of Al/FA Composites Fabricated by Compo Casting and the Equal Channel Angular Extrusion,” Processes, vol. 13, no. 4, Apr. 2025, doi: 10.3390/pr13040928.
[27] R. Soundararajan, A. Sathishkumar, S. Sivasankaran, G. Shanthosh, and S. Karthik, “Evaluation of Microstructures, Mechanical and Dry-Sliding Wear Performance of A356-(Fly Ash/SiCp) Hybrid Composites,” International Journal of Metalcasting, vol. 16, no. 4, pp. 2079–2096, Oct. 2022, doi: 10.1007/s40962-021-00731-3.
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Copyright (c) 2026 Mohammad Na'aim Abd Rahim, Mohd Shukor Salleh, Saifudin Hafiz Yahaya, Sivarao Subramonian, Azrin Hani Abdul Rashid, Salah Salman Al-Zubaidi, Muhammad Hisyam Abdul Aziz
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