journal article·2026-09Open access

Investigation of joint strength in PP-GF / aluminum hybrid components using a novel bulk forming process

Calvin Ebert, Philip Reitinger, Diego Rafael Alba, Andreas Hansen Gonçalves, Bedi Berk Karanlık, Mathias Liewald, Christian Bonten

Abstract

Abstract Hybrid components can effectively combine the advantageous properties of different materials, such as the excellent mechanical performance of metals and the light-weight characteristics of polymers. This study therefore investigates the manufacturing and mechanical performance of hybrid components comprising a metallic tube with a polymer core. The hybrid parts were produced by pressing a polymer into the metallic tube using a compression process at temperatures ranging from 100 °C to 150 °C, which is below the polymer’s melting temperature. This novel process differs significantly from conventional methods, such as injection molding with overmolding, as it enables simultaneous deformation of the metallic tube and forming of the plastic in solid state. To analyze the bond strength and assess the mechanical interlocking and adhesion at the interface, push-out tests and torsional loading experiments were conducted. The bond strength reached values of up to 8.4 MPa. Further, a finite element model was developed to simulate the forming process, enabling analysis of interfacial contact pressure, geometry variation, and local stress and strain states to provide deeper insights into material flow and deformation mechanisms.
Source: crossref · Quality: baseline

Research context

OpenAlex topics: Injection Molding Process and Properties · Polymer crystallization and properties · Electronic Packaging and Soldering Technologies

SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.

References (41)

Show source-provided references
1. Rafi HA (2024) Impact of composite materials on aircraft weight reduction, fuel efficiency, and performance in commercial aviation. ijme 04:21–35. https://doi.org/10.55640/ijme-04-01-0610.55640/ijme-04-01-06 ↗
2. Pizzi A (2003) In: Handbook of adhesive technology, 2. rev. and expanded. edn. Dekker, New York, Basel
3. Temesi T, Czigany T (2020) Integrated structures from dissimilar materials: the future belongs to aluminum–polymer joints. Adv Eng Mater 22. https://doi.org/10.1002/adem.20200000710.1002/adem.202000007 ↗
4. Deutsches Institut für Normung (2022) Fertigungsverfahren. Begriffe, Einteilung (DIN 8580)
5. Chey SY, Hong S, Kim DH et al (2025) The Effect of Laser Structuring on Hot-Press Joined Metal-Polymer Cross Tension Joints. Int J Precis Eng Manuf 26:961–976. https://doi.org/10.1007/s12541-025-01227-410.1007/s12541-025-01227-4 ↗
6. Du K, Huang J, Chen J et al (2020) Mechanical Property and Structure of Polypropylene/Aluminum Alloy Hybrid Prepared via Ultrasound-Assisted Hot-Pressing Technology. Mater (Basel) 13:236. https://doi.org/10.3390/ma1301023610.3390/ma13010236 ↗
7. Tolephih MH, Abood AN, Saad HM (2020) Hot Press Bonding of Aluminum Alloy AA6061-T6 to Polyamide and Polyamide Composites. IOP Conf Ser : Mater Sci Eng 671:12029. https://doi.org/10.1088/1757-899X/671/1/01202910.1088/1757-899X/671/1/012029 ↗
8. Lucchetta G, Marinello F, Bariani PF (2011) Aluminum sheet surface roughness correlation with adhesion in polymer metal hybrid overmolding. CIRP Ann 60:559–562. https://doi.org/10.1016/j.cirp.2011.03.07310.1016/j.cirp.2011.03.073 ↗
9. Kleffel T, Drummer D (2017) Investigating the suitability of roughness parameters to assess the bond strength of polymer-metal hybrid structures with mechanical adhesion. Compos Part B: Eng 117:20–25. https://doi.org/10.1016/j.compositesb.2017.02.04210.1016/j.compositesb.2017.02.042 ↗
10. Kajihara Y, Tamura Y, Kimura F et al (2018) Joining strength dependence on molding conditions and surface textures in blast-assisted metal-polymer direct joining. CIRP Ann 67:591–594. https://doi.org/10.1016/j.cirp.2018.04.11210.1016/j.cirp.2018.04.112 ↗
11. Kesten J, Armbruster D, Frölich F et al (2023) Electromechanical optimization of high reluctance torque variable flux machines under structural mechanical constraints. In: Electromechanical drive systems. Fachtagung VDE Wien 9:189–194
12. Li X, Liu F, Gong N et al (2017) Enhancing the joining strength of injection-molded polymer-metal hybrids by rapid heating and cooling. J Mater Process Technol 249:386–393. https://doi.org/10.1016/j.jmatprotec.2017.06.03410.1016/j.jmatprotec.2017.06.034 ↗
13. Vasconcelos RL, Oliveira GHM, Amancio-Filho ST et al (2023) Injection overmolding of polymer‐metal hybrid structures: A review. Polym Eng Sci 63:691–722. https://doi.org/10.1002/pen.2624410.1002/pen.26244 ↗
14. Farahani S (2018) Polymer injection forming: a new age technology for manufacturing polymer-metal hybrids. Dissertation, Clemson University
15. Hussain MM, Rauscher B, Trompeter M et al (2009) Potential of Melted Polymer as Pressure Medium in Sheet Metal Forming. KEM 410–411:493–501. https://doi.org/10.4028/www.scientific.net/KEM.410-411.49310.4028/www.scientific.net/KEM.410-411.493 ↗
16. Hussain MM, Trompeter M, Witulski J et al (2012) An experimental and numerical investigation on polymer melt injected sheet metal forming. J Manuf Sci Eng 134. https://doi.org/10.1115/1.400611710.1115/1.4006117 ↗
17. Lucchetta G, Baesso R (2007) Polymer Injection Forming (PIF) Of Thin-Walled Sheet Metal Parts — Preliminary Experimental Results. AIP Conf Proc 907:1046–1051. https://doi.org/10.1063/1.272965210.1063/1.2729652 ↗
18. Fang X, Kloska T (2020) Hybrid forming of sheet metals with long Fiber-reinforced thermoplastics (LFT) by a combined deep drawing and compression molding process. Int J Mater Form 13:561–575. https://doi.org/10.1007/s12289-019-01493-410.1007/s12289-019-01493-4 ↗
19. Hopmann C, Schild J, Wurzbacher S et al (2018) Combination technology of deep drawing and back-moulding for plastic/metal hybrid components. J Polym Eng 38:583–58910.1515/polyeng-2017-0354 ↗
20. Behrens B-A, Hübner S, Neumann A (2014) Forming Sheets of Metal and Fibre-reinforced Plastics to Hybrid Parts in One Deep Drawing Process. Procedia Eng 81:1608–1613. https://doi.org/10.1016/j.proeng.2014.10.19810.1016/j.proeng.2014.10.198 ↗
21. Bragança I, Silva C, Alves LM et al (2017) Lightweight joining of polymer and polymer-metal sheets by sheet-bulk forming. J Clean Prod 145:98–104. https://doi.org/10.1016/j.jclepro.2017.01.04910.1016/j.jclepro.2017.01.049 ↗
22. Baptista RJ, Pragana JP, Bragança IM et al (2021) Invisible mechanical lap joints for metal–polymer laminates. Proc Institution Mech Eng Part L: J Materials: Des Appl 235:320–328. https://doi.org/10.1177/146442072096214310.1177/1464420720962143 ↗
23. Baptista RJ, Pragana JP, Bragança IM et al (2020) Joining metal-polymer sandwich composite sheets with mechanical nuggets. CIRP Ann 69:249–252. https://doi.org/10.1016/j.cirp.2020.03.00810.1016/j.cirp.2020.03.008 ↗
24. Graf M, Härtel S, Binotsch C et al (2017) Forging of Lightweight Hybrid Metallic-Plastic Components. Procedia Eng 184:497–505. https://doi.org/10.1016/j.proeng.2017.04.12010.1016/j.proeng.2017.04.120 ↗
25. Härtel S, Kärger L, Meyer N et al (2019) How to combine plastics and light metals for forming processes and the influence of moisture content on forming behavior. In: The 22nd International Conference on Advances in Materials and Processing Technology (AMPT 2019). National Taiwan University of Science and Technology, p 119
26. Lambiase F, Scipioni SI, Lee C-J et al (2021) A state-of-the-art review on advanced joining processes for metal-composite and metal-polymer hybrid structures. Mater (Basel) 14. https://doi.org/10.3390/ma1408189010.3390/ma14081890 ↗
27. Blaga L, dos Santos JF, Bancila R et al (2015) Friction Riveting (FricRiveting) as a new joining technique in GFRP lightweight bridge construction. Constr Build Mater 80:167–179. https://doi.org/10.1016/j.conbuildmat.2015.01.00110.1016/j.conbuildmat.2015.01.001 ↗
28. Borba NZ, Blaga L, dos Santos JF et al (2018) Direct-Friction Riveting of polymer composite laminates for aircraft applications. Mater Lett 215:31–34. https://doi.org/10.1016/j.matlet.2017.12.03310.1016/j.matlet.2017.12.033 ↗
29. Lambiase F, Paoletti A (2018) Friction-assisted clinching of Aluminum and CFRP sheets. J Manuf Process 31:812–822. https://doi.org/10.1016/j.jmapro.2018.01.01410.1016/j.jmapro.2018.01.014 ↗
30. Willems F (2021) Vorhersage des Verformungsverhaltens langfaserverstärkter Thermoplaste unter ganzheitlicher Berücksichtigung der verarbeitungsbedingten Fasermikrostruktur. Dissertation, Universität Stuttgart
31. Bonten C (2019) Plastics Technology: Introduction and Fundamentals. Hanser, Munich10.3139/9781569907689 ↗
32. Willems F, Reitinger P, Bonten C (2020) Calibration of Fiber Orientation Simulations for LFT—A New Approach. J Compos Sci 4:163. https://doi.org/10.3390/jcs404016310.3390/jcs4040163 ↗
33. Deutsches Institut für Normung (2024) DIN EN ISO 527-2, Kunststoffe - Bestimmung der Zugeigenschaften. Teil 2, Prüfbedingungen für Form- und Extrusionsmassen (ISO/DIS 527-2:2024): Plastics - determination of tensile properties. Part 2, Test conditions for moulding and extrusion plastics (ISO/DIS 527-2:2024). Deutsche Norm. DIN Media GmbH, Berlin
34. Simões V, Laurent H, Oliveira M et al (2019) The influence of warm forming in natural aging and springback of Al-Mg-Si alloys. Int J Mater Form 12:57–68. https://doi.org/10.1007/s12289-018-1406-710.1007/s12289-018-1406-7 ↗
35. Shehata F, Painter MJ, Pearce R (1978) Warm forming of aluminium/magnesium alloy sheet. J Mech Working Technol 2:279–290. https://doi.org/10.1016/0378-3804(78)90023-210.1016/0378-3804(78)90023-2 ↗
36. Scapin M, Manes A (2018) Behaviour of Al6061-T6 alloy at different temperatures and strain-rates: Experimental characterization and material modelling. Mater Sci Engineering: A 734:318–328. https://doi.org/10.1016/j.msea.2018.08.01110.1016/j.msea.2018.08.011 ↗
37. Totten GE, MacKenzie DS (2003) Handbook of aluminum. CRC10.1201/9780203912591 ↗
38. Mahabunphachai S, Koç M (2010) Investigations on forming of aluminum 5052 and 6061 sheet alloys at warm temperatures. Mater Des (1980–2015) 31:2422–2434. https://doi.org/10.1016/j.matdes.2009.11.05310.1016/j.matdes.2009.11.053 ↗
39. Goncalves A (2024) Optimization of forming and material parameters for a polymer-metal bonding: a study on the design and development of hybrid components. master-thesis, Universität Stuttgart
40. Ferrer-Fabón B, Alms J, Behr M et al (2023) High‐resolution numerical simulations of polymer injection molding: analysis of mesh size and refinement. Proc Appl Math Mech 23. https://doi.org/10.1002/pamm.20230024510.1002/pamm.202300245 ↗
41. Alba DR, Ebert C, Reitinger P et al (2025) Hybrid forming of metal-polymer gears: A feasibility assessment. Mater Res Proc 54:1354–1363. https://doi.org/10.21741/9781644903599-14710.21741/9781644903599-147 ↗