Cooling Slope-Cast LM25 Aluminum Fabrication for Additive Friction Stir Deposition: A Microstructural and Mechanical Study
DOI:
https://doi.org/10.15282/ijame.22.4.2025.12.0989Keywords:
Additive friction stir deposition, Cooling slope casting, Aluminum alloy feedstock, T6 heat treatment, Solid-state additive manufacturingAbstract
Additive Friction Stir Deposition (AFSD) is an innovative solid-state additive manufacturing (AM) technique that has offered a promising solution for joining and fabricating high-performance aluminum alloys over the past decade. However, the use of heat-treated feedstock produced by cooling slope casting (CSC) remains largely unexplored. This initial study investigates the feasibility of using CSC LM25 feedstock in AFSD to achieve better microstructure and hardness, while preventing early feedstock breakage. Microstructural examination indicated a shift from coarse dendritic to globular grains, with an average grain size of 1.828 µm (0.351-60.835 µm), a reduction of approximately 96.3% compared to the as-cast material. While some samples (notably C5 CSC_HT and D2 PMC_HT) achieved smooth, defect-free deposition, continuous deposits under higher rotational speed (800 rpm) and feed rate (3 mm/min), the hardness of deposited parts reduced to 63–72 HV compared to 89HV in the base material, reflecting a ~20–29% decline due to thermal softening, over-aging of precipitates, and Si coarsening during AFSD thermal cycles. Although CSC helped to refine the grain structure and enhance deposition flow, this alone was not enough to improve the mechanical behavior of the deposited parts. Additional processing steps, such as thixoforming or heat treatment after deposition, may be needed to achieve better results. This study offers early observations on how cast feedstock behaves in AFSD and identifies important challenges and future directions for improving the solid-state processing of aluminum alloys, especially for lightweight parts in aerospace and automotive applications.
References
[1] H. Ravinath, I. I. Ahammed, P. H., S. A. Devan., V R. A. Senan, K.V. Shankar, et al., “Impact of aging temperature on the metallurgical and dry sliding wear behaviour of LM25 / Al2O3 metal matrix composite for potential automotive application,” International Journal of Lightweight Materials and Manufacture, vol. 6, no. 3, pp. 416–43, 2023.
[2] P. Suresh, P. Arunagiri, and A. P. Arun Pravin, “Experimental analysis of aluminium alloy LM25 with carbon in composite material,” in Materials Today: Proceedings, Elsevier, Jan 2020, pp. 7–12.
[3] K. Surani, M.V. Galindo, H. Patel, V.I. Velkin, M.I. Haque Siddiqui, A. Kumar, et al., “Effect of copper addition on mechanical properties and microstructures of LM25 cast alloys,” AIP Advances, vol. 14, no. 4, p. 045025, 2024.
[4] K. Sunitha, K. Gurusami, N. Rajeswari, A. Kathikraja, and L. Saravanan, “Investigation of mechanical properties of SiC particle reinforced Aluminium A356 / LM25 alloy composite,” in Materials Today: Proceedings, Elsevier Ltd, Jan. 2022, pp. 1983–1987.
[5] M. Zhang, F.C. Liu, Z.Y. Liu, P. Xue, P. Dong, H. Zhang, et al., “Highly stable nanoscale amorphous microstructure at steel-aluminum interface enabled by a new solid-state additive manufacturing method,” Scripta Materialia, vol. 227, p. 115300, 2023.
[6] J. Liu, Y. Miao, R. Wu, C. Wei, Y. Zhao, Y. Wu, et al., “Effect of heat treatment on microstructure, mechanical properties and corrosion resistance of 7075 aluminum alloys fabricated by improved friction stir additive manufacturing,” Journal of Alloys and Compounds, vol. 1007, p. 176512, 2024.
[7] F. Liu, P. Dong, A.S. Khan, Y. Zhang, R. Cheng, A. Taub, et al., “3D printing of fine-grained aluminum alloys through extrusion-based additive manufacturing: Microstructure and property characterization,” Journal of Materials Science & Technology, vol. 139, pp. 126–136, 2023.
[8] H. Hanizam, M. S. Salleh, M. Z. Omar, A. B. Sulong, and M. A. M. Arif, “Effects of hybrid processing on microstructural and mechanical properties of thixoformed aluminum matrix composite,” Journal of Alloys and Compounds, vol. 836, p. 155378, 2020.
[9] M. S. Salleh, H. Hashim, M.Z. Omar, A.B. Sulong, S. Abd Rahman, S.H. Yahaya, 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, 2020.
[10] Z. McClelland, K. Dunsford, B. Williams, H. Petersen, K. Devami, M. Weaver, et al., “Microstructure and mechanical behavior comparison between cast and additive friction stir-deposited high-entropy alloy Al0.35CoCrFeNi,” Materials, vol. 17, no. 4, p. 910, 2024.
[11] E. Yasa, O. Poyraz, A. Molyneux, A. Sharman, G. M. Bilgin, and J. Hughes, “Systematic review on additive friction stir deposition: Materials, processes, monitoring and modelling,” Inventions, vol. 9, no. 6, 2024.
[12] R. S. Mishra, R. S. Haridas, and P. Agrawal, “Friction stir-based additive manufacturing,” Science and Technology of Welding and Joining, vol. 27, no. 3, pp. 141–165, 2022.
[13] J. Shao, A. Samaei, T. Xue, X. Xie, S. Guo, J. Cao, et al., “Additive friction stir deposition of metallic materials: Process, structure and properties,” Mater Des, vol. 234, 2023.
[14] R. J. Griffiths, A. E. Wilson-Heid, M. A. Linne, E. V. Garza, A. Wright, and A. A. Martin, “Additive friction stir deposition of a tantalum–tungsten refractory alloy,” Journal of Manufacturing and Materials Processing, vol. 8, no. 4, p. 177, 2024.
[15] B. Alzahrani, M.M.E.S. Seleman, M.M.Z. Ahmed, E. Elfishawy, Ahmed, A.M.Z., Touileb, K., et al., “The applicability of die cast A356 alloy to additive friction stir deposition at various feeding speeds,” Materials, vol. 14, no. 20, p. 6018, 2021.
[16] J. J. S. Dilip and G. D. Janaki Ram, “Microstructure evolution in aluminum alloy AA 2014 during multilayer friction deposition,” Materials Characterization, vol. 86, pp. 146–151, 2013.
[17] V. Soni, R.L. Menchaca, D. Davis, N.N. Kumar, M. Gonzalez, P. Awasthi, et al., “Process-specific design strategy enables exceptional as-deposited strength-ductility synergy in novel Al–Ce alloys via additive friction stir deposition (AFSD),” Journal of Materials Research and Technology, vol. 35, pp. 1889–1900, 2025.
[18] 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, 2022.
[19] D. K. Yadav and I. Chakrabarty, “Effect of cooling slope casting and partial remelting treatment on microstructure and mechanical properties of A319-xMg2Si In-Situ composites,” Materials Science and Engineering: A, vol. 791, p. 139790, 2020.
[20] M. A. H. Safian, M. S. Salleh, S. Subramonian, N. I. S. Hussein, M. A. Sulaiman, and S. H. Yahaya, “Production of LM4 feedstock for thixoforming using cooling slope casting,” Journal of Advanced Manufacturing Technology, vol. 11, no. 1, pp. 77–90, 2017.
[21] Z. Li, Y. Li, R. Zhou, L. Xie, Q. Wang, L. Zhang, et al., “Microstructure and properties of semi-solid 7075 aluminum alloy processed with an enclosed cooling slope channel,” Crystals (Basel), vol. 13, no. 7, p. 1102, 2023.
[22] H. A. Ibrahim and M. M. Saeed Mulapeer, “Semi-solid casting of aluminum alloy using a cooling slope technic,” Zanco Journal of Pure and Applied Sciences, vol. 32, no. 3, pp. 49–56, 2020.
[23] S. Samat, M. Z. Omar, I. F. Mohamed, A. H. Baghdadi, and A. M. Aziz, “A comparative study on microstructure, mechanical property and damping capacity of hypoeutectic Al–Si–Cu alloy for different casting technologies,” International Journal of Metalcasting, vol. 19, no. 2, pp. 1180-1193, 2024.
[24] R. M. Said, M. R. M. Kamal, N. H. Hussin, S. M. Suhaili, S. H. H. Anuar, A. Samsuddin, et al., “Modeling and prediction of the mechanical properties of feedstock by cooling-slope casting process using MOJaya algorithm,” Journal of Advanced Research in Applied Mechanics, vol. 121, no. 1, pp. 13–26, 2024.
[25] P. Das, “Microstructure and mechanical properties of cooling slope rheocast Al-7Si-0.3Mg alloy and development of a rheo pressure die cast knuckle housing,” Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science, vol. 54, no. 1, pp. 395–424, 2023.
[26] T. Tugiman, A. Thayab, F. Ariani, T. Sitorus, S. Suhandi, and R. Rizki, “The Effect of Cooling Slope on Mechanical Properties of Aluminum-8.5wt.% Si Alloy Produced by Gravity Casting,” in Proceedings of the 2nd Annual Conference of Engineering and Implementation on Vocational Education (ACEIVE 2018), 3rd November 2018, North Sumatra, 2019.
[27] L. Chen, L. Zhu, L. Lu, Z. Yang, X. Ren, and X. Zhang, “The effect of heat treatment on the microstructure and electrochemical corrosion behavior of multilayer AA6061 alloy fabricated by additive friction stir deposition,” Applied Surface Science, vol. 650, p. 159167, 2024.
[28] E. Yasa, O. Poyraz, K. Do, A. Molyneux, J. McManus, and J. Hughes, “In-situ monitoring and control of additive friction stir deposition,” Materials, vol. 18, no. 7, p. 1509, 2025.
[29] Q. Qiao, M. Zhou, X. Gong, S. Jiang, Y. Lin, H. Wang, et al., “In-situ monitoring of additive friction stir deposition of AA6061: Effect of layer thickness on the microstructure and mechanical properties,” Additive Manufacturing, vol. 84, p. 104141, 2024.
[30] M. Zhang, T. Jiang, X. Feng, Y. Xie, Y. Su, Z. Sun, et al., “Investigation on in-situ tensile behaviors of 6061 aluminum alloy fabricated by wire additive friction stir deposition,” Journal of Alloys and Compounds, vol. 1008, p. 176780, 2024.
[31] N. Gotawala and H. Z. Yu, “Material flow path and extreme thermomechanical processing history during additive friction stir deposition,” Journal of Manufacturing Processes, vol. 101, pp. 114–127, 2023.
[32] L. P. Martin, A. Luccitti, and M. Walluk, “Repair of aluminum 6061 plate by additive friction stir deposition,” International Journal of Advanced Manufacturing Technology, vol. 118, no. 3–4, pp. 759–773, 2022.
[33] M. M. Z. Ahmed, M. M. El-Sayed Seleman, E. Ahmed, H. A. Reyad, N. A. Alsaleh, and I. Albaijan, “A novel friction stir deposition technique to refill keyhole of friction stir spot welded AA6082-T6 dissimilar joints of different sheet thicknesses,” Materials, vol. 15, no. 19, p. 6799, 2022.
[34] D. Traiano, S. do Nascimento Rosa, L. A. Lourençato, A. Sánchez Roca, M. C. Sánchez Orozco, and H. D. Carvajal Fals, “Multiresponse optimization applied to friction-stir processing to enhance wear and corrosion performance in Al–Si alloys,” Discover Applied Sciences, vol. 6, no. 12, p. 643, 2024.
[35] Z. Shen, M. Zhang, D. Li, X. Liu, S. Chen, W. Hou, et al., “Microstructural characterization and mechanical properties of AlMg alloy fabricated by additive friction stir deposition,” International Journal of Advanced Manufacturing Technology, vol. 125, no. 5–6, pp. 2733–2741, 2023.
[36] A. I. Abdel-Aziz, A. S. A. A. Taleb, Z. M. El-Baradie, and A. I. Z. Farahat, “Effect of friction stir processing on the microstructure and mechanical properties of A384 aluminum alloy,” Key Engineering Materials, vol. 786, pp. 23–36, 2018.
[37] Y. G. Y. Elshaghoul, M.M. El-Sayed Seleman, A. Bakkar, S.A. Elnekhaily, I. Albaijan, M.M.Z. Ahmed, et al., “Additive friction stir deposition of AA7075-T6 alloy: Impact of process parameters on the microstructures and properties of the continuously deposited multilayered parts,” Applied Sciences (Switzerland), vol. 13, no. 18, p. 10255, 2023.
[38] P. Vijayavel, V. Balasubramanian, and I. Rajkumar, “Effect of tool traverse speed on strength, hardness, and ductility of friction-stir-processed LM25AA-5% SiCp metal matrix composites,” Metallography, Microstructure, and Analysis, vol. 7, no. 3, pp. 321–333, 2018.
[39] M. R. S. Ganesh, N. Reghunath, M. J.Levin, A. Prasad, S. Doondi, and K. V. Shankar, “Strontium in Al–Si–Mg Alloy: A Review,” Metals and Materials International, vol. 28, no. 1, pp. 1–40, 2022.
[40] S. Vellingiri, “An experimental and investigation on the micro-structure hardness and tensile properties of Al-GrFe3O4 hybrid metal matrix composites,” FME Transactions, vol. 47, no. 3, pp. 511–517, 2019.
[41] M. Abbasi-Nahr, S. E. Mirsalehi, and S. S. Mirhosseini, “Additive manufacturing of AA5083/TiN-Diamond hybrid nanocomposite parts via additive friction stir deposition: Metallurgical structure, mechanical, tribological, and electrochemical properties,” Journal of Materials Research and Technology, vol. 30, pp. 8187–8208, 2024.
[42] M. Abbasi–Nahr and S. E. Mirsalehi, “Additive friction stir deposition of AA5083/MoS2-diamond hybrid nanocomposites: Investigating their metallurgical, mechanical, tribological, and electrochemical characteristics, and process-structure-property relationships,” Journal of Alloys and Compounds, vol. 1013, 2025.
[43] N. F. B. W. Anuar, M. S. Salleh, M. Z. Omar, W. F. H. W. Zamri, S. H. Y. Yahaya, and A. M. Ali, “Effect of T6 heat treatment on microstructure and hardness properties of thixoformed graphene-reinforced A356 composites,” Journal of Advanced Manufacturing Technology, vol. 17, no. 1, pp. 73–85, 2023.
[44] X. Feng, M. Zhang, T. Jiang, Y. Xie, Z. Sun, and W. Li, “Additive friction stir deposition of an Al-Cu-Mg alloy: Microstructure evolution and mechanical properties,” Materials Characterization, vol. 218, p. 114562, 2024.
[45] X. Zhu, R. Wang, L. Wang, M. Liu, and S. Li, “Effect of rotational shear and heat input on the microstructure and mechanical properties of large-diameter 6061 aluminium alloy additive friction stir deposition,” Crystals (Basel), vol. 14, no. 7, p. 581, 2024.
[46] N. I. Palya, K. Fraser, N. Zhu, J.B. Hoarston, K. Doherty, P.G. Allison, et al., “Microstructure prediction from smooth particle hydrodynamics process simulations of additive friction stir deposition,” Metallurgical and Materials Transactions A, vol. 55A, no. 9, pp. 3601–3616, 2024.
[47] R. P. Kinser, N. Zhu, M.B. Williams, T.W. Rushing, K.J. Doherty, P.G. Allison, et al., “Effects on microstructure and mechanical properties of aluminum alloy 6061 processed via underwater additive friction stir deposition,” Journal of Manufacturing Processes, vol. 134, pp. 932–942, 2025.
[48] M. Zhang, X. Ye, Y. Li, H. Wang, R. Lai, and Y. Li, “Effect of heat treatment states of feedstock on the microstructure and mechanical properties of AA2219 layers deposited by additive friction stir deposition,” Materials, vol. 16, no. 24, p. 7591, 2023.
[49] Z. Y. Ma, S. R. Sharma, and R. S. Mishra, “Effect of friction stir processing on the microstructure of cast A356 aluminum,” Materials Science and Engineering: A, vol. 433, no. 1–2, pp. 269–278, 2006.
[50] M. M. Z. Ahmed, S. Ataya, M. M. El-Sayed Seleman, A. M. A. Mahdy, N. A. Alsaleh, and E. Ahmed, “Heat input and mechanical properties investigation of friction stir welded AA5083/AA5754 and AA5083/AA7020,” Metals (Basel), no. 11, p. 68, 2021.
[51] M. M. Z. Ahmed, S. Ataya, M. M. E. S. Seleman, T. Allam, N. A. Alsaleh, and E. Ahmed, “Grain structure, crystallographic texture, and hardening behavior of dissimilar friction stir welded AA5083-O and AA5754-H14,” Metals (Basel), vol. 11, no. 2, pp. 1–16, 2021.
[52] M. M. Jalilvand, Y. Mazaheri, A. Heidarpour, and M. Roknian, “Development of A356/Al2O3 + SiO2 surface hybrid nanocomposite by friction stir processing,” Surface and Coatings Technology, vol. 360, pp. 121–132, 2019.
[53] M. Zhang, T. Jiang, Y. Su, Z. Sun, Y. Xu, and W. Li, “Study on the interfacial bonding behavior of dissimilar aluminum alloys via additive friction stir deposition,” Progress in Natural Science: Materials International, vol. 35, no. 2, pp. 433–439, 2025.
[54] M. Dong, Y. Li, T. Chen, C. Du, and X. Ren, “Solid-state additive manufacturing of dissimilar 7075–2024 aluminum alloys by additive friction stir deposition: Interfacial bonding and process optimization,” Journal of Materials Processing Technology, vol. 343, p. 118989, 2025.
[55] L. Karthick, M. Mruthunjaya, S. Srinivas, R. Prasanna Venkatesh, N.K. Gurajala, M. Mothilal, et al., “Influence of tool pin profiles on aluminium alloy A356 and ceramic-based nanocomposites for light-weight structures by friction stir processing,” Advances in Materials Science and Engineering, vol. 2024, p. 2494900, 2024.
Downloads
Published
Issue
Section
License
Copyright (c) 2025 The Author(s)
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
