Manufacturing methods of functionally graded materials: a comprehensive review

Year 2025, Volume: 1 Issue: 1, 6 - 20, 28.02.2025

Burak İkinci

Abstract

Various problems arise in traditional composites and the gradient of these materials needs to be controlled for more specific purposes. At this stage, functionally graded materials, which are a more specific area of advanced composites, come into play. High strength-to-weight ratio, wear resistance, thermal insulation, controlled porosity and many other features can be obtained by using functionally graded materials. A wide variety of functionally graded materials and their manufacturing methods are available. In this study, the classifications of properties of functionally graded materials and manufacturing methods in the literature are examined. The basic principles for each method are presented. In addition to the advantages and disadvantages of the methods, the difficulties in the production phase are also examined.

Keywords

functionally graded, classification, manufacturing methods, composites, advantages

References

• Wang, S. S. (1983). Fracture mechanics for delamination problems in composite materials. Journal of Composite Materials, 17(3), 210-223. https://doi.org/10.1177/002199838301700302
• Gürdal, Z., Haftka, R. T., & Hajela, P. (1999). Design and optimization of laminated composite materials. John Wiley & Sons.
• Nikbakt, S. K. M. S. S., Kamarian, S., & Shakeri, M. (2018). A review on optimization of composite structures Part I: Laminated composites. Composite Structures, 195, 158-185. https://doi.org/10.1016/j.compstruct.2018.03.063
• Şimşek, M. (2015). Bi-directional functionally graded materials (BDFGMs) for free and forced vibration of Timoshenko beams with various boundary conditions. Composite Structures, 133, 968-978.https://doi.org/10.1016/j.compstruct.2015.08.021
• Najibi, A., & Mokhtari, T. (2023). Functionally graded materials for knee and hip arthroplasty; an update on design, optimization, and manufacturing. Composite Structures, 117350. https://doi.org/10.1016/j.compstruct.2023.117350
• El-Galy, I. M., Saleh, B. I., & Ahmed, M. H. (2019). Functionally graded materials classifications and development trends from industrial point of view. SN Applied Sciences, 1, 1-23. https://doi.org/10.1007/s42452-019-1413-4
• Gasik, M. M. (1998). Micromechanical modelling of functionally graded materials. Computational Materials Science, 13(1-3), 42-55. https://doi.org/10.1016/S0927-0256(98)00044-5
• Zhang, R., Jiang, F., Xue, L., & Yu, J. (2022). Review of additive manufacturing techniques for large-scale metal functionally graded materials. Crystals, 12(6), 858. https://doi.org/10.3390/cryst12060858
• Yao, L., Ramesh A., Xiao, Z., Chen, Y., & Zhuang, Q. (2023). Multimetal research in powder bed fusion: a review. Materials, 16(12), 4287. https://doi.org/10.3390/ma16124287
• Mahmoud, D., & Elbestawi, M. A. (2017). Lattice structures and functionally graded materials applications in additive manufacturing of orthopedic implants: a review. Journal of Manufacturing and Materials Processing, 1(2), 13. https://doi.org/10.3390/jmmp1020013
• Zhang, C., Chen, F., Huang, Z., Jia, M., Chen, G., Ye, Y., ... & Lavernia, E. J. (2019). Additive manufacturing of functionally graded materials: A review. Materials Science and Engineering: A, 764, 138209. https://doi.org/10.1016/j.msea.2019.138209
• Wei, C., Sun, Z., Chen, Q., Liu, Z., & Li, L. (2019). Additive manufacturing of horizontal and 3D functionally graded 316L/Cu10Sn components via multiple material selective laser melting. Journal of Manufacturing Science and Engineering, 141(8), 081014. https://doi.org/10.1115/1.4043983
• Nemat-Alla, M. (2003). Reduction of thermal stresses by developing two-dimensional functionally graded materials. International journal of solids and structures, 40(26), 7339-7356. https://doi.org/10.1016/j.ijsolstr.2003.08.017
• Sharma, P., & Khinchi, A. (2023). Finite element modeling of two-directional FGM beams under hygrothermal effect. International Journal on Interactive Design and Manufacturing (IJIDeM), 1-8. https://doi.org/10.1007/s12008-022-01190-8
• Ghazwani, M. H., Alnujaie, A., Avcar, M., & Van Vinh, P. (2024). Examination of the high-frequency behavior of functionally graded porous nanobeams using nonlocal simple higher-order shear deformation theory. Acta Mechanica, 1-20. https://doi.org/10.1007/s00707-024-03858-6
• Zhang, J. Z., McAvoy, D. T., Halpern, B. L., Schmitt, J. J., Zanoni, R., & Schaschek, K. (1994). Jet vapor deposition of organic guest-inorganic host thin films for optical and electronic applications. Journal of electronic materials, 23, 1239-1244. https://doi.org/10.1007/BF02649976
• Wood, M., & Ward-Close, M. (1995). Fibre-reinforced intermetallic compounds by physical vapour deposition. Materials Science and Engineering: A, 192, 590-596. https://doi.org/10.1016/0921-5093(94)03282-3
• Groves, J. F., & Wadley, H. N. G. (1997). Functionally graded materials synthesis via low vacuum directed vapor deposition. Composites Part B: Engineering, 28(1-2), 57-69. https://doi.org/10.1016/S1359-8368(96)00023-6
• Fathi, R., Wei, H., Saleh, B., Radhika, N., Jiang, J., Ma, A., Ostrikov, K. K. (2022). Past and present of functionally graded coatings: Advancements and future challenges. Applied Materials Today, 26, 101373.. https://doi.org/10.1016/j.apmt.2022.101373
• Saeed, M., Alshammari, Y., Majeed, S. A., & Al-Nasrallah, E. (2020). Chemical vapour deposition of graphene—Synthesis, characterisation, and applications: A review. Molecules, 25(17), 3856. https://doi.org/10.3390/molecules25173856
• Nur-E-Alam, M., Basher, M. K., Vasiliev, M., & Das, N. (2021). Physical vapor-deposited silver (Ag)-based metal-dielectric nanocomposites for thin-film and coating applications. Applied Sciences, 11(15), 6746. https://doi.org/10.3390/app11156746
• Bhavar, V., Kattire, P., Thakare, S., & Singh, R. K. P. (2017, September). A review on functionally gradient materials (FGMs) and their applications. In IOP conference series: materials science and engineering, 229(1), 012021. https://doi.org/10.1088/1757-899X/229/1/012021
• Grammes, T., Emmerich, T., & Aktaa, J. (2021). W/EUROFER functionally graded coatings for plasma facing components: Technology transfer to industry and upscaling. Fusion Engineering and Design, 173, 112940. https://doi.org/10.1016/j.fusengdes.2021.112940
• Ramesh, M., Karthik, A., James, D. J. D., & Pandiyan, G. K. (2023). Functionally graded materials: review on manufacturing by Liquid and gas based techniques. Materials Research Express, 10(8), 085305. https://doi.org/10.1088/2053-1591/acf1f1
• Hirai, T., & Sasaki, M. (1991). Vapor-deposited functionally gradient materials. JSME international journal. Ser. 1, Solid mechanics, strength of materials, 34(2), 123-129. https://doi.org/10.1299/jsmea1988.34.2_123
• Choy, K. L. (2003). Chemical vapour deposition of coatings. Progress in materials science, 48(2), 57-170. https://doi.org/10.1016/S0079-6425(01)00009-3
• Wang, X., Chu, X., Zhao, H., Lu, S., Fang, F., Li, J., ... & Wang, X. (2014). Controllable growth of functional gradient ZnO material using chemical vapor deposition. Integrated Ferroelectrics, 151(1), 1-6. https://doi.org/10.1080/10584587.2014.898552
• Jin, G., Takeuchi, M., Honda, S., Nishikawa, T., & Awaji, H. (2005). Properties of multilayered mullite/Mo functionally graded materials fabricated by powder metallurgy processing. Materials Chemistry and Physics, 89(2-3), 238-243. https://doi.org/10.1016/j.matchemphys.2004.03.031
• Übeyli, M., Balci, E., Sarikan, B., Öztaş, M. K., Camuşcu, N., Yildirim, R. O., & Keleş, Ö. (2014). The ballistic performance of SiC–AA7075 functionally graded composite produced by powder metallurgy. Materials & Design, 56, 31-36. https://doi.org/10.1016/j.matdes.2013.10.092
• Erdemir, F., Canakci, A., & Varol, T. (2015). Microstructural characterization and mechanical properties of functionally graded Al2024/SiC composites prepared by powder metallurgy techniques. Transactions of Nonferrous Metals Society of China, 25(11), 3569-3577. https://doi.org/10.1016/S1003-6326(15)63996-6
• Tripathy, A., Sarangi, S. K., & Panda, R. (2017). Fabrication of functionally graded composite material using powder metallurgy route: an overview. Int. J. Mech. Prod. Eng. Res. Dev, 7(6), 135-145.
• Liang, J., Zhang, G., Zhou, Y., Song, S., Zuo, X., & Wang, H. (2022). The Microstructure and the Properties of 304 and 430 Steel Foams Prepared by Powder Metallurgy Using CaCl2 as a Space Holder. Metals, 12(7), 1182. https://doi.org/10.3390/met12071182
• Mishra, S. K., & Pathak, L. C. (2009). Self-propagating high-temperature synthesis (SHS) of advanced high-temperature ceramics. Key Engineering Materials, 395, 15-38. https://doi.org/10.4028/www.scientific.net/KEM.395.15
• Yong, C., Xunjia, S., Genliang, H., & YaKun, X. (2013, March). Research on self-propagating high temperature synthesis prepared ZrC-ZrB2 composite ceramic. In Journal of Physics: Conference Series., 419(1), 012057. IOP Publishing. https://doi.org/10.1088/1742-6596/419/1/012057
• Parihar, R. S., Setti, S. G., & Sahu, R. K. (2018). Recent advances in the manufacturing processes of functionally graded materials: a review. Science and Engineering of Composite Materials, 25(2), 309-336. https://doi.org/10.1[]5/secm-2015-0395
• Liechty, B. C., & Webb, B. W. (2008). Flow field characterization of friction stir processing using a particle-grid method. Journal of Materials Processing Technology, 208(1-3), 431-443. https://doi.org/10.1016/j.jmatprotec.2008.01.008
• Karthikeyan, L., Senthilkumar, V. S., & Padmanabhan, K. A. (2010). On the role of process variables in the friction stir processing of cast aluminum A319 alloy. Materials & Design, 31(2), 761-771. https://doi.org/10.1016/j.matdes.2009.08.001
• Fu, P. X., Kang, X. H., Ma, Y. C., Liu, K., Li, D. Z., & Li, Y. Y. (2008). Centrifugal casting of TiAl exhaust valves. Intermetallics, 16(2), 130-138. https://doi.org/10.1016/j.intermet.2007.08.007
• Rajan, T. P. D., Pillai, R. M., & Pai, B. C. (2008). Centrifugal casting of functionally graded aluminium matrix composite components. International Journal of Cast Metals Research, 21(1-4), 214-218. https://doi.org/10.1179/136404608X361972
• Sobczak, J. J., & Drenchev, L. (2013). Metallic functionally graded materials: a specific class of advanced composites. Journal of Materials Science & Technology, 29(4), 297-316. https://doi.org/10.1016/j.jmst.2013.02.006
• Singh, S. P., Rohith, R. P., Nirmal, S. F., Raja, D. E., & Ravichandran, P. (2024). Improvement in manufacturing of aluminium-based functionally graded materials through centrifugal casting—A review. Engineering Proceedings, 61(1), 16. https://doi.org/10.3390/engproc2024061016
• Mercadelli, E., Sanson, A., Pinasco, P., Roncari, E., & Galassi, C. (2010). Tape cast porosity-graded piezoelectric ceramics. Journal of the European Ceramic Society, 30(6), 1461-1467. https://doi.org/10.1016/j.jeurceramsoc.2009.12.004
• Schafföner, S., & Aneziris, C. G. (2012). Pressure slip casting of coarse grain oxide ceramics. Ceramics International, 38(1), 417-422. https://doi.org/10.1016/j.ceramint.2011.06.064
• Baskin, D. M., Zimmerman, M. H., Faber, K. T., & Fuller, E. R. (1997). Forming single‐phase laminates via the gelcasting technique. Journal of the American Ceramic Society., 80(11), 2929-2932. https://doi.org/10.1111/j.1151-2916.1997.tb03213.x
• Zimmerman, M. H., Faber, K. T., & Fuller Jr, E. R. (1997). Forming textured microstructures via the gelcasting technique. Journal of the American Ceramic Society, 80(10), 2725-2729. https://doi.org/10.1111/j.1151-2916.1997.tb03184.x
• Topateş, G., Akça, E., Tür, Y. K., & Duran, C. (2024). Functionally graded Al2O3‐based ceramic systems by gel casting method. International Journal of Applied Ceramic Technology, 22(1), e14898. https://doi.org/10.1111/ijac.14898
• Sofie, S. W. (2007). Fabrication of functionally graded and aligned porosity in thin ceramic substrates with the novel freeze–tape‐casting process. Journal of the American Ceramic Society, 90(7), 2024-2031. https://doi.org/10.1111/j.1551-2916.2007.01720.x
• Scanlan, M., Browne, D. J., & Bates, A. (2005). New casting route to novel functionally gradient light alloys. Materials Science and Engineering: A, 413, 66-71. https://doi.org/10.1016/j.msea.2005.09.004
• Rahvard, M. M., Tamizifar, M., Boutorabi, M. A., & Shiri, S. G. (2014). Effect of superheat and solidified layer on achieving good metallic bond between A390/A356 alloys fabricated by cast-decant-cast process. Transactions of Nonferrous Metals Society of China, 24(3), 665-672. https://doi.org/10.1016/S1003-6326(14)63109-5
• Kruth, J. P. (1991). Material incress manufacturing by rapid prototyping techniques. CIRP annals, 40(2), 603-614. https://doi.org/10.1016/S0007-8506(07)61136-6
• Bikas, H., Stavropoulos, P., & Chryssolouris, G. (2016). Additive manufacturing methods and modelling approaches: a critical review. The International Journal of Advanced Manufacturing Technology, 83, 389-405. https://doi.org/10.1007/s00170-015-7576-2
• Guessasma, S., Tao, L., Belhabib, S., Zhu, J., Zhang, W., & Nouri, H. (2018). Analysis of microstructure and mechanical performance of polymeric cellular structures designed using stereolithography. European Polymer Journal, 98, 72-82. https://doi.org/10.1016/j.eurpolymj.2017.10.034
• Pagac, M., Hajnys, J., Ma, Q. P., Jancar, L., Jansa, J., Stefek, P., & Mesicek, J. (2021). A review of vat photopolymerization technology: materials, applications, challenges, and future trends of 3D printing. Polymers, 13(4), 598. https://doi.org/10.3390/polym13040598
• Wang, J., & Shaw, L. L. (2006). Fabrication of functionally graded materials via inkjet color printing. Journal of the American Ceramic Society, 89(10), 3285-3289. https://doi.org/10.1111/j.1551-2916.2006.01206.x
• Chen, Y., Ye, L., Kinloch, A. J., & Zhang, Y. X. (2022). 3D printed carbon-fibre reinforced composite lattice structures with good thermal-dimensional stability. Compos. Sci. Technol., 227, 109599. https://doi.org/10.1016/j.compscitech.2022.109599
• Garg, A., Sharma, A., Zheng, W., & Li, L. (2025). A review on artificial intelligence-enabled mechanical analysis of 3D printed and FEM-modelled auxetic metamaterials. Virtual and Physical Prototyping, 20(1), e2445712. https://doi.org/10.1080/17452759.2024.2445712
• Wang, Y., Müller, W. D., Rumjahn, A., & Schwitalla, A. (2020). Parameters influencing the outcome of additive manufacturing of tiny medical devices based on PEEK. Materials, 13(2), 466. https://doi.org/10.3390/ma13020466
• Alkunte, S., Fidan, I., Naikwadi, V., Gudavasov, S., Ali, M. A., Mahmudov, M., ... & Cheepu, M. (2024). Advancements and Challenges in Additively Manufactured Functionally Graded Materials: A Comprehensive Review. Journal of Manufacturing and Materials Processing, 8(1), 23. https://doi.org/10.3390/jmmp8010023
• Sireesha, M., Lee, J., Kiran, A. S. K., Babu, V. J., Kee, B. B., & Ramakrishna, S. (2018). A review on additive manufacturing and its way into the oil and gas industry. RSC advances, 8(40), 22460-22468. https://doi.org/10.1039/C8RA03194K
• Nian, Y., Wan, S., Avcar, M., Yue, R., & Li, M. (2023). 3D printing functionally graded metamaterial structure: Design, fabrication, reinforcement, optimization. International Journal of Mechanical Sciences, 258, 108580. https://doi.org/10.1016/j.ijmecsci.2023.108580
• Han, C., Li, Y., Wang, Q., Cai, D., Wei, Q., Yang, L., ... & Shi, Y. (2018). Titanium/hydroxyapatite (Ti/HA) gradient materials with quasi-continuous ratios fabricated by SLM: material interface and fracture toughness. Materials & Design, 141, 256-266. https://doi.org/10.1016/j.matdes.2017.12.037
• Ansari, P., Rehman, A. U., Pitir, F., Veziroglu, S., Mishra, Y. K., Aktas, O. C., & Salamci, M. U. (2021). Selective laser melting of 316l austenitic stainless steel: Detailed process understanding using multiphysics simulation and experimentation. Metals, 11(7), 1076. https://doi.org/10.3390/met11071076
• Del Val, J., Arias-González, F., Barro, O., Riveiro, A., Comesaña, R., Penide, J., ... & Pou, J. (2017). Functionally graded 3D structures produced by laser cladding. Procedia Manufacturing, 13, 169-176. https://doi.org/10.1016/j.promfg.2017.09.029
• Lai, Q., Abrahams, R., Yan, W., Qiu, C., Mutton, P., Paradowska, A., & Soodi, M. (2017). Investigation of a novel functionally graded material for the repair of premium hypereutectoid rails using laser cladding technology. Composites Part B: Engineering, 130, 174-191. https://doi.org/10.1016/j.compositesb.2017.07.089
• Liu, W., & DuPont, J. N. (2003). Fabrication of functionally graded TiC/Ti composites by laser engineered net shaping. Scripta Materialia, 48(9), 1337-1342. https://doi.org/10.1016/S1359-6462(03)00020-4
• Kim, H., Cong, W., Zhang, H. C., & Liu, Z. (2017). Laser engineered net shaping of nickel-based superalloy Inconel 718 powders onto AISI 4140 alloy steel substrates: Interface bond and fracture failure mechanism. Materials, 10(4), 341. https://doi.org/10.3390/ma10040341
• Rahmani, R., Lopes, S. I., & Prashanth, K. G. (2023). Selective laser melting and spark plasma sintering: a perspective on functional biomaterials. Journal of Functional Biomaterials, 14(10), 521. https://doi.org/10.3390/jfb14100521
• Tofail, S. A., Koumoulos, E. P., Bandyopadhyay, A., Bose, S., O’Donoghue, L., & Charitidis, C. (2018). Additive manufacturing: scientific and technological challenges, market uptake and opportunities. Materials today, 21(1), 22-37. https://doi.org/10.1016/j.mattod.2017.07.001
• Pompe, W., Worch, H., Epple, M., Friess, W., Gelinsky, M., Greil, P., ... & Schulte, K. J. M. S. (2003). Functionally graded materials for biomedical applications. Materials Science and Engineering: A, 362(1-2), 40-60. https://doi.org/10.1016/S0921-5093(03)00580-X
• Murr, L. E., Martinez, E., Amato, K. N., Gaytan, S. M., Hernandez, J., Ramirez, D. A., ... & Wicker, R. B. (2012). Fabrication of metal and alloy components by additive manufacturing: examples of 3D materials science. Journal of Materials Research and Technology, 1(1), 42-54. https://doi.org/10.1016/S2238-7854(12)70009-1
• Corbin, S. F., Zhao-Jie, X., Henein, H., & Apte, P. S. (1999). Functionally graded metal/ceramic composites by tape casting, lamination and infiltration. Materials Science and Engineering: A, 262(1-2), 192-203. https://doi.org/10.1016/S0921-5093(98)01019-3
• Zahedi, A. M., Rezaie, H. R., Javadpour, J., Mazaheri, M., & Haghighi, M. G. (2009). Processing and impact behavior of Al/SiCp composites fabricated by the pressureless melt infiltration method. Ceramics International, 35(5), 1919-1926. https://doi.org/10.1016/j.ceramint.2008.10.024
• Drevet, R., Fauré, J., & Benhayoune, H. (2024). Electrophoretic Deposition of Bioactive Glass Coatings for Bone Implant Applications: A Review. Coatings, 14(9), 1084. https://doi.org/10.3390/coatings14091084
• Ghosh, S., Haldar, S., Gupta, S., Chauhan, S., Mago, V., Roy, P., & Lahiri, D. (2022). Single unit functionally graded bioresorbable electrospun scaffold for scar-free full-thickness skin wound healing. Biomaterials Advances, 139, 212980. https://doi.org/10.1016/j.bioadv.2022.212980
• Li, D., & Xia, Y. (2004). Electrospinning of nanofibers: reinventing the wheel?. Advanced materials, 16(14), 1151-1170. https://doi.org/10.1002/adma.200400719
• Greiner, A., & Wendorff, J. H. (2007). Electrospinning: a fascinating method for the preparation of ultrathin fibers. Angewandte Chemie International Edition, 46(30), 5670-5703. https://doi.org/10.1002/anie.200604646
• Qasim, S. B., Najeeb, S., Delaine-Smith, R. M., Rawlinson, A., & Rehman, I. U. (2017). Potential of electrospun chitosan fibers as a surface layer in functionally graded GTR membrane for periodontal regeneration. Dental Materials, 33(1), 71-83. https://doi.org/10.1016/j.dental.2016.10.003
• Russo, F., Ursino, C., Avruscio, E., Desiderio, G., Perrone, A., Santoro, S., ... & Figoli, A. (2020). Innovative Poly (Vinylidene Fluoride)(PVDF) electrospun nanofiber membrane preparation using DMSO as a low toxicity solvent. Membranes, 10(3), 36. https://doi.org/10.3390/membranes10030036
• Jayachandran, M., Tsukamoto, H., Sato, H., & Watanabe, Y. (2013). Formation Behavior of Continuous Graded Composition in Ti‐ZrO2 Functionally Graded Materials Fabricated by Mixed‐Powder Pouring Method. Journal of Nanomaterials, 2013(1), 504631. https://doi.org/10.1155/2013/504631
• Pakseresht, A. H., Ghasali, E., Nejati, M., Shirvanimoghaddam, K., Javadi, A. H., & Teimouri, R. (2015). Development empirical-intelligent relationship between plasma spray parameters and coating performance of Yttria-Stabilized Zirconia. The International Journal of Advanced Manufacturing Technology, 76, 1031-1045. https://doi.org/10.1007/s00170-014-6212-x
• Lim, Y. M., Park, Y. J., Yun, Y. H., & Hwang, K. S. (2002). Functionally graded Ti/HAP coatings on Ti–6Al–4V obtained by chemical solution deposition. Ceramics International, 28(1), 37-41. https://doi.org/10.1016/S0272-8842(01)00055-4
• Besra, L., & Liu, M. (2007). A review on fundamentals and applications of electrophoretic deposition (EPD). Progress in Materials Science, 52(1), 1-61. https://doi.org/10.1016/j.pmatsci.2006.07.001
• Shailesh, P., Sundarrajan, S., & Komaraiah, M. (2014). Optimization of process parameters of Al-Si alloy by centrifugal casting technique using Taguchi design of experiments. Procedia Materials Science, 6, 812-820. https://doi.org/10.1016/j.mspro.2014.07.098
• Arsha, A. G., Jayakumar, E., Rajan, T. P. D., Antony, V., & Pai, B. C. (2015). Design and fabrication of functionally graded in-situ aluminium composites for automotive pistons. Materials & Design, 88, 1201-1209. https://doi.org/10.1016/j.matdes.2015.09.099
• Wang, F., Jiang, K., & Xu, X. (2009). Gel casting of stainless steel powder through mold DIS process. Tsinghua Science and Technology, 14(S1), 216-222. https://doi.org/10.1016/S1007-0214(09)70095-1
• Tallon, C., & Franks, G. V. (2011). Recent trends in shape forming from colloidal processing: A review. Journal of the Ceramic Society of Japan, 119(1387), 147-160. https://doi.org/10.2109/jcersj2.119.147
• Yeo, J. G., Jung, Y. G., & Choi, S. C. (1998). Design and microstructure of ZrO2/SUS316 functionally graded materials by tape casting. Materials Letters, 37(6), 304-311. https://doi.org/10.1016/S0167-577X(98)00111-6
• Fu, C., Chan, S. H., Liu, Q., Ge, X., & Pasciak, G. (2010). Fabrication and evaluation of Ni-GDC composite anode prepared by aqueous-based tape casting method for low-temperature solid oxide fuel cell. International Journal of Hydrogen Energy, 35(1), 301-307. https://doi.org/10.1016/j.ijhydene.2009.09.101
• Katayama, T., Sukenaga, S., Saito, N., Kagata, H., & Nakashima, K. (2011, October). Fabrication of Al2O3-W functionally graded materials by slipcasting method. In IOP Conference Series: Materials Science and Engineering, 18(20), 202023. IOP Publishing. http://dx.doi.org/10.1088/1757-899X/18/20/202023
• Bulatova, R., Bahl, C., Andersen, K., Kuhn, L. T., & Pryds, N. (2015). Functionally Graded Ceramics Fabricated with Side‐by‐Side Tape Casting for Use in Magnetic Refrigeration. International Journal of Applied Ceramic Technology, 12(4), 891-898. https://doi.org/10.1111/ijac.12298
• Santos, L. N. R. M., Silva, J. R. S., Cartaxo, J. M., Rodrigues, A. M., Neves, G. A., & Menezes, R. R. (2021). Freeze-casting applied to ceramic materials: a short review of the influence of processing parameters. Ceramica, 67, 1-13. https://doi.org/10.1590/0366-69132021673812923
• Anandavel, B., Mohamed Nazirudeen, S. S., Anburaj, J., & Angelo, P. C. (2015). Development and Characterization of Functionally Gradient Al–Si Alloy Using Cast-Decant-Cast Process. Transactions of the Indian Institute of Metals, 68, 137-145. https://doi.org/10.1007/s12666-015-0527-7
• Nagarajan, D., & Mohana Sivam, P. (2016). Microstructure and Wear Behavior of a Functionally Gradient Al–Si Alloy Prepared Using the Cast–Decant–Cast (CDC) Process. Materials Performance and Characterization, 5(5), 637-647. https://doi.org/10.1520/MPC20160055
• Hanaor, D., Michelazzi, M., Veronesi, P., Leonelli, C., Romagnoli, M., & Sorrell, C. (2011). Anodic aqueous electrophoretic deposition of titanium dioxide using carboxylic acids as dispersing agents. Journal of the European Ceramic Society, 31(6), 1041-1047. https://doi.org/10.1016/j.jeurceramsoc.2010.12.017
• Farnoush, H., Mohandesi, J. A., & Çimenoğlu, H. (2015). Micro-scratch and corrosion behavior of functionally graded HA-TiO2 nanostructured composite coatings fabricated by electrophoretic deposition. Journal of the Mechanical Behavior of Biomedical Materials, 46, 31-40. https://doi.org/10.1016/j.jmbbm.2015.02.021
• F42 Committee. (2016). Terminology for additive manufacturing-general principles-terminology. ASTM International.
• Halloran, J. W. (2016). Ceramic stereolithography: additive manufacturing for ceramics by photopolymerization. Annual Review of Materials Research, 46(1), 19-40. https://doi.org/10.1146/annurev-matsci-070115-031841
• Li, L., Bellehumeur C, S., & Gu, P. (2001). Composite modeling and analysis of FDM prototypes for design and fabrication of functionally graded parts. http://dx.doi.org/10.26153/tsw/3262
• Cho, J. R., & Ha, D. (2002). Optimal tailoring of 2D volume-fraction distributions for heat-resisting functionally graded materials using FDM. Computer Methods in Applied Mechanics and Engineering, 191(29-30), 3195-3211. https://doi.org/10.1016/S0045-7825(02)00256-6
• Scaffaro, R., Lopresti, F., Maio, A., Sutera, F., & Botta, L. (2017). Development of polymeric functionally graded scaffolds: A brief review. Journal of Applied Biomaterials & Functional Materials, 15(2), 107-121. https://doi.org/10.5301/jabfm.5000332
• Lowen, J. M., & Leach, J. K. (2020). Functionally graded biomaterials for use as model systems and replacement tissues. Advanced functional materials, 30(44), 1909089. https://doi.org/10.1002/adfm.201909089
• Hong, C. Q., Zhang, X. H., Li, W. J., Han, J. C., & Meng, S. H. (2008). A novel functionally graded material in the ZrB2–SiC and ZrO2 system by spark plasma sintering. Materials Science and Engineering: A, 498(1-2), 437-441. https://doi.org/10.1016/j.msea.2008.08.032
• Kawasaki, A., & Watanabe, R. (1997). Concept and P/M fabrication of functionally gradient materials. Ceramics International, 23(1), 73-83. https://doi.org/10.1016/0272-8842(95)00143-3
• Dermeik, B., & Travitzky, N. (2020). Laminated object manufacturing of ceramic‐based materials. Advanced engineering materials, 22(9), 2000256. https://doi.org/10.1002/adem.202000256
• Gan, Y. X., Solomon, D., & Reinbolt, M. (2010). Friction stir processing of particle reinforced composite materials. Materials, 3(1), 329-350. https://doi.org/10.3390/ma3010329
• Rathee, S., Maheshwari, S., & Siddiquee, A. N. (2018). Issues and strategies in composite fabrication via friction stir processing: a review. Materials and Manufacturing Processes, 33(3), 239-261. https://doi.org/10.1080/10426914.2017.1303162
• Santhosh, V., Prakash, D. A., Murugan, K., & Babu, N. (2020). Thermo-mechanical analysis of Tailor-made functionally graded materials through Friction stir processing. Materials today: Proc., 33, 4445-4449. https://doi.org/10.1016/j.matpr.2020.07.687
• Sam, M., Jojith, R., & Radhika, N. (2021). Progression in manufacturing of functionally graded materials and impact of thermal treatment—A critical review. Journal of Manufacturing Processes, 68, 1339-1377. https://doi.org/10.1016/j.jmapro.2021.06.062
• Lin, X., Yue, T. M., Yang, H. O., & Huang, W. D. (2005). Laser rapid forming of SS316L/Rene88DT graded material. Materials Science and Engineering: A, 391(1-2), 325-336. https://doi.org/10.1016/j.msea.2004.08.072
• Andertová, J., Tláskal, R., Maryška, M., & Havrda, J. (2007). Functional gradient alumina ceramic materials—Heat treatment of bodies prepared by slip casting method. Journal of the European Ceramic Society, 27(2-3), 1325-1331. https://doi.org/10.1016/j.jeurceramsoc.2006.04.088
• Traini, T., Mangano, C., Sammons, R. L., Mangano, F., Macchi, A., & Piattelli, A. (2008). Direct laser metal sintering as a new approach to fabrication of an isoelastic functionally graded material for manufacture of porous titanium dental implants. Dental Materials, 24(11), 1525-1533. https://doi.org/10.1016/j.dental.2008.03.029
• Mahmoud, E. R. I., Takahashi, M., Shibayanagi, T., & Ikeuchi, K. (2009). Effect of friction stir processing tool probe on fabrication of SiC particle reinforced composite on aluminium surface. Science and Technology of Welding and Joining, 14(5), 413-425. https://doi.org/10.1179/136217109X406974
• Gandra, J., Miranda, R., Vilaça, P., Velhinho, A., & Teixeira, J. P. (2011). Functionally graded materials produced by friction stir processing. Journal of Materials Processing Technology, 211(11), 1659-1668. https://doi.org/10.1016/j.jmatprotec.2011.04.016
• Sudarmadji, N., Tan, J. Y., Leong, K. F., Chua, C. K., & Loh, Y. T. (2011). Investigation of the mechanical properties and porosity relationships in selective laser-sintered polyhedral for functionally graded scaffolds. Acta Biomaterialia, 7(2), 530-537. https://doi.org/10.1016/j.actbio.2010.09.024
• Wang, K., Sun, W., Li, B., Xue, H., & Liu, C. (2011). Microstructures in centrifugal casting of SiC p/AlSi9Mg composites with different mould rotation speeds. Journal of Wuhan University of Technology-Mater, 26, 504-509. https://doi.org/10.1007/s11595-011-0257-6
• Mahamood, R. M., Akinlabi, E. T., Shukla, M., & Pityana, S. L. (2012). Functionally graded material: an overview.
• CPM, S. A., Varghese, B., & Baby, A. (2014). A review on functionally graded materials. Int. J. Eng. Sci, 3, 90-101.
• Rikhtegar, F., & Shabestari, S. G. (2014). Investigation on solidification conditions in functionally Si-gradient Al alloys using simulation and cooling curve analysis methods. Journal of Thermal Analysis and Calorimetry, 117, 721-729. https://doi.org/10.1007/s10973-014-3767-6
• Bai, H., Chen, Y., Delattre, B., Tomsia, A. P., & Ritchie, R. O. (2015). Bioinspired large-scale aligned porous materials assembled with dual temperature gradients. Science advances, 1(11), e1500849. https://doi.org/10.1126/sciadv.1500849
• Mahamood, R. M., & Akinlabi, E. T. (2015). Laser metal deposition of functionally graded Ti6Al4V/TiC. Materials & Design, 84, 402-410. https://doi.org/10.1016/j.matdes.2015.06.135
• Tsukamoto, H. (2015). Microstructure and indentation properties of ZrO2/Ti functionally graded materials fabricated by spark plasma sintering. Materials Science and Engineering: A., 640, 338-349. https://doi.org/10.1016/j.msea.2015.06.005
• Nie, T., Xue, L., Ge, M., Ma, H., & Zhang, J. (2016). Fabrication of poly (L-lactic acid) tissue engineering scaffolds with precisely controlled gradient structure. Materials Letters, 176, 25-28. https://doi.org/10.1016/j.matlet.2016.04.078
• Moravcik, I., Cizek, J., Kovacova, Z., Nejezchlebova, J., Kitzmantel, M., Neubauer, E., ... & Dlouhy, I. (2017). Mechanical and microstructural characterization of powder metallurgy CoCrNi medium entropy alloy. Materials Science and Engineering: A., 701, 370-380. https://doi.org/10.1016/j.msea.2017.06.086
• Naviroj, M., Voorhees, P. W., & Faber, K. T. (2017). Suspension-and solution-based freeze casting for porous ceramics. Journal of Materials Research, 32(17), 3372-3382. https://doi.org/10.1557/jmr.2017.133
• Sharma, A., Bandari, V., Ito, K., Kohama, K., Ramji, M., & BV, H. S. (2017). A new process for design and manufacture of tailor-made functionally graded composites through friction stir additive manufacturing. Journal of Manufacturing Processes, 26, 122-130. https://doi.org/10.1016/j.jmapro.2017.02.007
• Zygmuntowicz, J., Wiecińska, P., Miazga, A., Konopka, K., & Kaszuwara, W. (2017). Al 2 O 3/Ni functionally graded materials (FGM) obtained by centrifugal-slip casting method. Journal of Thermal Analysis and Calorimetry, 130, 123-130. https://doi.org/10.1007/s10973-017-6232-5
• Omidi, N., Jabbari, A. H., & Sedighi, M. (2018). Mechanical and microstructural properties of titanium/hydroxyapatite functionally graded material fabricated by spark plasma sintering. Powder Metallurgy, 61(5), 417-427. https://doi.org/10.1080/00325899.2018.1535391
• Owoputi, A. O., Inambao, F. L., & Ebhota, W. S. (2018). A review of functionally graded materials: fabrication processes and applications. International Journal of Applied Engineering Research, 13(23), 16141-16151.
• Sarathchandra, D. T., Subbu, S. K., & Venkaiah, N. (2018). Functionally graded materials and processing techniques: An art of review. Materials today: Proc., 5(10), 21328-21334. https://doi.org/10.1016/j.matpr.2018.06.536
• Khoo, W., Chung, S. M., Lim, S. C., Low, C. Y., Shapiro, J. M., & Koh, C. T. (2019). Fracture behavior of multilayer fibrous scaffolds featuring microstructural gradients. Materials & Design, 184, 108184. https://doi.org/10.1016/j.matdes.2019.108184
• Odhiambo, J. G., Li, W., Zhao, Y., & Li, C. (2019). Porosity and its significance in plasma-sprayed coatings. Coatings, 9(7), 460. https://doi.org/10.3390/coatings9070460
• Saleh, B., Jiang, J., Fathi, R., Al-Hababi, T., Xu, Q., Wang, L., ... & Ma, A. (2020). 30 Years of functionally graded materials: An overview of manufacturing methods, Applications and Future Challenges. Composites Part B: Engineering, 201, 108376.https://doi.org/10.1016/j.compositesb.2020.108376
• Srinivas, P. N. S., & Balakrishna, B. (2020). Microstructural, mechanical and tribological characterization on the Al based functionally graded material fabricated powder metallurgy. Materials Research Express, 7(2), 026513. https://doi.org/10.1088/2053-1591/ab6f41
• Xiong, Y. Z., Gao, R. N., Zhang, H., Dong, L. L., Li, J. T., & Li, X. (2020). Rationally designed functionally graded porous Ti6Al4V scaffolds with high strength and toughness built via selective laser melting for load-bearing orthopedic applications. Journal of the Mechanical Behavior of Biomedical Materials, 104, 103673. https://doi.org/10.1016/j.jmbbm.2020.103673
• Yan, L., Chen, Y., & Liou, F. (2020). Additive manufacturing of functionally graded metallic materials using laser metal deposition. Additive Manufacturing, 31, 100901. https://doi.org/10.1016/j.addma.2019.100901
• Reichardt, A., Shapiro, A. A., Otis, R., Dillon, R. P., Borgonia, J. P., McEnerney, B. W., ... & Beese, A. M. (2021). Advances in additive manufacturing of metal-based functionally graded materials. International Materials Reviews, 66(1), 1-29. https://doi.org/10.1080/09506608.2019.1709354
• Singh, D. D., Arjula, S., & Reddy, A. R. (2021). Functionally graded materials manufactured by direct energy deposition: a review. Materials today: Proc., 47, 2450-2456. https://doi.org/10.1016/j.matpr.2021.04.536
• Goudarzi, Z. M., Valefi, Z., Zamani, P., & Taghi-Ramezani, S. (2022). Comparative investigation of the effect of composition and porosity gradient on thermo-mechanical properties of functionally graded thick thermal barrier coatings deposited by atmospheric plasma spraying. Ceramics International, 48(19), 28800-28814. https://doi.org/10.1016/j.ceramint.2021.12.307
• Kashkarov, E. B., Krotkevich, D. G., Mingazova, Y. R., Pushilina, N. S., Syrtanov, M. S., Lider, A. M., & Travitzky, N. (2022). Functionally graded laminated composites fabricated from MAX-phase filled preceramic papers: microstructure, mechanical properties and oxidation resistance. Journal of the European Ceramic Society, 42(5), 2062-2072. https://doi.org/10.1016/j.jeurceramsoc.2022.01.023
• Pasha, A., & Rajaprakash, B. M. (2022). Functionally graded materials (FGM) fabrication and its potential challenges & applications. Materials Today: Proceedings, 52, 413-418. https://doi.org/10.1016/j.matpr.2021.09.077