Experimental Investigation of the Influence of Notch Geometry on Impact Resistance of Al/Cu Bimetallic Sheets
Main Article Content
Abstract
The impact resistance of bimetallic materials is a critical aspect of engineering, particularly in the aerospace and automotive industries. Notched geometries are often encountered in real-world scenarios due to manufacturing defects or intentional design features. The present work investigates the impact resistance and fracture behavior of Al/Cu bimetallic sheets, focusing on the influence of notches on fracture energy, the fracture process zone, and overall failure mechanisms. For interpretation and analyses purposes, the impact test results were integrated with SEM fractographic analysis and the Essential Work of Fracture (EWF) framework. Four notch dimensions of U and V geometries were tested. Experimental results indicated that U-notches yielded higher fracture toughness and lower stress concentration factors. Conversely, V-notch specimens experienced a 32.5% reduction in toughness and a 25.5% increase in stress concentration as notch depth increased. Also, the Analytical EWF predictions showed good agreement with experimental data provide that Al/Cu obey the fracture ductile behavior. The SEM images emphasized on the ductile fracture nature of the Al/Cu sheet, and U-notches reveal a wider and rougher fracture area shows larger FPZ. As well, as the Al layer exhibited ductile plastic deformation, while the Cu layer showed brittle cleavage and acted as a structural hinge to arrest cracks. These findings provide critical insight into enhancing the use of bimetallic metals under dynamic loading, establishing a basis for future investigations into the relationship between bimetallic parameters and fracture behavior.
Downloads
Article Details
Section
How to Cite
References
Alaie, A., Hashemi, R. and Kazemi, F., 2021. Investigation of forming limit diagram and mechanical properties of the bimetallic Al/Cu composite sheet at different temperatures fabricated by explosive welding. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 235(1–2), pp. 1–12. https://doi.org/10.1177/0954405420949227
Anderson, T.L., 2017. Fracture Mechanics: Fundamentals and Applications. 4th ed. Boca Raton: CRC Press.
ASTM E23-02a, 2002. Standard test methods for notched bar impact testing of metallic materials. ASTM International.
Avcı, U. and Erdoğdu, Y.E., 2021. Microstructure and mechanical properties of a semi‑centrifugal compression processed Al6013 and Cu bimetal. Materials Testing, 63(5), pp. 471–478.
Chen, C.Y., Chen, H.L. and Hwang, W.S., 2006. Influence of interfacial structure development on the fracture mechanism and bond strength of aluminium/copper bimetal plate. Materials Transactions, 47(4), pp. 1232–1239. https://doi.org/10.2320/matertrans.47.1232
Chen, J. and Cao, R., 2014. Micromechanism of cleavage fracture of metals: a comprehensive microphysical model for cleavage cracking in metals. Butterworth-Heinemann. https://doi.org/10.1016/B978-0-08-100499-1.00001-7
Deng, Y., Zhang, C., Shao, J. and Li, W., 2022. Modeling the effect of temperature and notch root radius on fracture toughness. Frontiers in Materials, 9, 990314. https://doi.org/10.3389/fmats.2022.990314
El Etri, H., Korkmaz, M.E., Gupta, M.K., Gunay, M. and Xu, J., 2022. A state‑of‑the‑art review on mechanical characteristics of different fiber metal laminates for aerospace and structural applications. International Journal of Advanced Manufacturing Technology, 123, pp. 2965–2991. https://doi.org/10.1007/s00170-022-10277-1
Harrigan, J., McClure, P., McNulty, R., McCabe, R. and Reddy, V., 2022. Towards standardizing the preparation of test specimens made with material extrusion: review of current techniques for tensile testing. Additive Manufacturing, 58, 103050. https://doi.org/10.1016/j.addma.2022.103050
Hertzberg, R.W., 1995. Deformation and fracture mechanics of engineering materials. 4th ed. Hoboken: John Wiley & Sons.
Hilhorst, A., Pardoen, T., and Jacques, P. J., 2022. Optimization of the essential work of fracture method for characterization of the fracture resistance of metallic sheets. Engineering Fracture Mechanics, 268, 108442. https://doi.org/10.1016/j.engfracmech.2022.108442
Hosseinzadeh, A., Farhangdoost, K., Maraki, M.R. and Sadidi, M., 2022. Investigation of the effect of notch tip radius and notch depth on Charpy fracture energy in 7075‑T651 aluminium alloy. International Journal of Advanced Design and Manufacturing Technology, 13(2), pp. 65–72. https://doi.org/10.1080/00084433.2022.2066241
ISO 148-1, 2016. Charpy impact test on metals—Determination of impact strength using U-notch and V-notch specimens. International Organization for Standardization
Jiang, S., Zhang, H., Li, X., and Wang, J., 2021. Fracture mechanics analysis of bimaterial interface cracks using the generalized finite difference method. Theoretical and Applied Fracture Mechanics, 113, 102942. https://doi.org/10.1016/j.tafmec.2021.102942
Kaya, Y., 2018. Investigation of copper–aluminium composite materials produced by explosive welding. Metals, 8(10), P. 780. https://doi.org/10.3390/met8100780
Krishnan, A., and Xu, L. R. 2013. An experimental study on the crack initiation from notches connected to interfaces of bonded bi‑materials. Engineering Fracture Mechanics, 111, pp. 65–76. https://doi.org/10.1016/j.engfracmech.2013.08.010
Lee, J., Jo, W., Seo, J. and An, G., 2025. Effect of notch shape on the fracture toughness behavior. Journal of the Society of Naval Architects of Korea, pp. 2092–6782. https://doi.org/10.1016/j.ijnaoe.2025.100646
Lei Z., Zhang B., Liu G., Zhao T., Zhang Z., Gao H., Cai J., and Wang, K., 2023. Study on microstructure evolution and fracture behavior of Al/Al/Cu multilayer composites. Journal of Materials Research and Technology, 25, pp. 5307–5317. https://doi.org/10.1016/j.jmrt.2023.07.014
Li, X.B., Yang, Y., Xu, Y.S. and Zu, G.Y., 2018. Deformation behavior and crack propagation on interface of Al/Cu laminated composites in uniaxial tensile test. Rare Metals, 39(2), pp. 296–303. https://doi.org/10.1016/S1003-6326(19)65069-7
Montgomery, D. C., 2019. Design and analysis of experiments.10th ed. John Wiley & Sons.
Motamedi, M.A., Torabi, A.R. and Hashemi, R., 2024. Notch strength evaluation for highly ductile Al/Cu bi-metal fabricated by the roll-bonding technique under pure mode I and pure mode II loading conditions. Theoretical and Applied Fracture Mechanics, 129. https://doi.org/10.1016/j.tafmec.2024.104435
Omiya, M., Arakawa, S., Yao, Z., Muramatsu, M., Nishi, S., Takada, K., Murata, M., Okato, K., Ogawa, K., Oide, K., Kobayashi, T., Han, J. and Terada, K., 2022. Influence of strength and notch shape on crack initiation and propagation behavior of advanced high strength steel sheets. Engineering Fracture Mechanics, 271, 108573. https://doi.org/10.1016/j.engfracmech.2022.108573
Pardoen, T., Marchal, Y., and Delannay, F., 2002. Essential work of fracture compared to fracture mechanics—Towards a thickness independent plane stress toughness. Engineering Fracture Mechanics, 69(5), pp. 617–631. https://doi.org/10.1016/S0013-7944(01)00099-6
Rösler, J., Harders, H. and Bäker, M., 2007. Mechanical behaviour of engineering materials. Berlin Heidelberg: Springer.
Rahmatabadi, D., 2018. Fracture toughness investigation of Al1050/Cu/MgAZ31ZB multi‑layered composite produced by accumulative roll bonding process. Materials Science and Engineering A, 734, pp. 427–437. https://doi.org/10.1016/j.msea.2018.08.017
Romanowski, M., Łukianowicz, C., Sutowska, M., Zawadka, W., Pimenov, D.Y. and Nadolny, K., 2021. Assessment of the technological quality of X5CrNi18 10 steel parts after laser and abrasive water jet cutting using a synthetic index of technological quality. Materials, 14(17), P. 4801. https://doi.org/10.3390/ma14174801
Schroeder C. J., Parrington R. J., Maciejewski J. O., and Lane, J. F., 2024. Revised ASM handbook: Vol. 12: Fractography. ASM International.
Shajari, Y., Ghasemi, R., Zarei‑Hanzaki, A. and Abedi, H., 2022. Formation of intermetallic compounds in Al–Cu interface via cold roll bonding: A review. Surface Engineering and Applied Electrochemistry, 58(1), pp. 41–50. https://doi.org/10.3103/S1068375522010112
Torabi, A.R., Mirzavand, M., Saboori, B. and Cicero, S., 2023. Fracture behavior of AA7075–AA6061 and AA7075–Cu friction-stir welded joints containing blunt V-notches under opening-mode loading. Materials, 16. https://doi.org/10.3390/ma16030789
Trzepieciński, T., Najm, S.M., Sbayti, M., Belhadjsalah, H., Szpunar, M. and Lemu, H.G., 2021. New advances and future possibilities in forming technology of hybrid metal–polymer composites used in aerospace applications. Journal of Composites Science, 5(8), 217. https://doi.org/10.3390/jcs5080217
Wang, R., Zhao, Q. and Li, M., 2025. Interface microstructure and corrosion resistance of T2 Cu/6061 aluminum composites produced by explosion welding. Journal of Materials Research and Technology, 39, pp. 4745–4757. https://doi.org/10.1016/j.jmrt.2025.10.168
Wang, X., Li, F., Chen, S. and Cao, L., 2019. SEM analysis of microvoid coalescence and dimple morphology in ductile fracture of steels under dynamic loading. International Journal of Impact Engineering, 130, pp. 537–548. https://doi.org/10.1016/j.ijimpeng.2019.05.001.
Wong, W.J. and Walters, C.L., 2025. Damage mechanics model for correlating notch toughness in Charpy impact tests with fracture toughness in cracked static fracture tests. Engineering Fracture Mechanics, 320, 111043. https://doi.org/10.1016/j.engfracmech.2025.111043
Xu, S., Zhang, H., Shen, W., Luo, W. and Zhang, Y., 2025. Mechanical behavior of marine aluminum alloy sheet under low-speed impact resistance. Chinese Journal of Ship Research, 20, p.148. https://doi.org/10.19693/j.issn.1673-3185.03648
Yousefi Mehr, V. and Toroghinejad, M.R., 2024. Mode I fracture analysis of aluminum-copper bimetal composite using finite element method. Heliyon, 10(4), e26329. https://doi.org/10.1016/j.heliyon.2024.e26329