{ "id": "epdr4shzaj", "slug": "impact-welding", "title": "Impact welding", "updated": "2026-10-15", "topic_path": [ { "id": "technology", "label": "Technology and the built world", "api_url": "https://www.edgepedia.org/api/v1/topics/technology" }, { "id": "technology.engineering", "label": "Engineering and manufacturing", "api_url": "https://www.edgepedia.org/api/v1/topics/technology.engineering" }, { "id": "technology.engineering.manufacturing.processes", "label": "Manufacturing processes and fabrication", "api_url": "https://www.edgepedia.org/api/v1/topics/technology.engineering.manufacturing.processes" }, { "id": "technology.engineering.manufacturing.processes.welding-soldering-and-joining", "label": "Welding, soldering, and joining", "api_url": "https://www.edgepedia.org/api/v1/topics/technology.engineering.manufacturing.processes.welding-soldering-and-joining" } ], "geo": [ { "id": "geo.nongeo.t1946.technology.engineering.manufacturing.processes", "label": "Non-geographic · 1946 to 2000: Manufacturing processes and fabrication", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.technology.engineering.manufacturing.processes", "path": [ { "id": "geo.nongeo", "label": "Non-geographic", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo" }, { "id": "geo.nongeo.t1946", "label": "Non-geographic · 1946 to 2000", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946" }, { "id": "geo.nongeo.t1946.technology", "label": "Technology and the built world", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.technology" }, { "id": "geo.nongeo.t1946.technology.engineering", "label": "Engineering and manufacturing", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.technology.engineering" }, { "id": "geo.nongeo.t1946.technology.engineering.manufacturing.processes", "label": "Manufacturing processes and fabrication", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.technology.engineering.manufacturing.processes" } ] } ], "excerpt": "Impact welding is a solid-state joining method that bonds similar or dissimilar metals by driving a flyer plate into a target at several hundred meters per second.", "snippet": "Impact welding is a solid-state joining method that bonds similar or dissimilar metals by driving a flyer plate into a target at several hundred meters per second.", "node": "technology.engineering.manufacturing.processes.welding-soldering-and-joining", "markdown": "# Impact welding\n\nImpact welding is a solid-state joining method that bonds similar or dissimilar metals by driving a flyer plate (the metal plate accelerated into the target to bond) into a target at several hundred meters per second at an oblique angle, producing a metallurgical bond without bulk melting. Five variants share one mechanism and differ only in the energy source: gas gun welding (GGW), [explosive welding](https://www.edgepedia.org/explosive-welding) (EXW), [magnetic pulse welding](https://www.edgepedia.org/magnetic-pulse-welding) (MPW), vaporizing foil actuator welding (VFAW), and laser impact welding (LIW).[1](https://www.mdpi.com/2075-4701/9/2/144) The process is valued for dissimilar-metal pairs, which fusion welding joins poorly, and it leaves no heat-affected zone.[2](https://mse.osu.edu/sites/default/files/uploads/mrs_bulletin_aug_2019_vfaw_article.pdf)\n\n| Key fact | Value |\n|---|---|\n| Variants | GGW, EXW, MPW, VFAW, LIW; same mechanism, different energy source[1](https://www.mdpi.com/2075-4701/9/2/144) |\n| Impact conditions | Typically above 300 m/s at 10°–30° oblique[2](https://mse.osu.edu/sites/default/files/uploads/mrs_bulletin_aug_2019_vfaw_article.pdf); successful welding normally 200–700 m/s at 5°–25°[3](https://www.sciencedirect.com/science/article/abs/pii/S1526612518311083) |\n| Bonding time | Several to dozens of microseconds; under 1 µs in LIW[1](https://www.mdpi.com/2075-4701/9/2/144) |\n| Joint efficiency | Close to 100% for AA5052 and AA6111 welded to DP980 and boron steels[2](https://mse.osu.edu/sites/default/files/uploads/mrs_bulletin_aug_2019_vfaw_article.pdf) |\n| Thickness ranges | VFAW: 0.2–3 mm sheets, 5–20 mm spot diameter; EXW: 5–50 mm plates; LIW: below 0.2 mm[4](https://www.sciencedirect.com/science/article/abs/pii/S0142112324006546) |\n| EXW track record | First U.S. patent filed by Philipchuk et al. in 1962; more than 200 material combinations welded, including Fe/Ti, Al/Ti, and Al/Fe[1](https://www.mdpi.com/2075-4701/9/2/144) |\n| VFAW pressure | About 1 GPa instantaneous pressure from input energies of no more than 10 kJ[5](https://www.osti.gov/servlets/purl/1416747) |\n\n## How it works\n\nThe flyer approaches the target at several hundred meters per second and strikes at an oblique angle. At the moving collision point, a jet is ejected that carries the contaminants, oxide layers, and a thin layer of metal with it, exposing clean metal surfaces that bond within atomic distance.[1](https://www.mdpi.com/2075-4701/9/2/144) Jetting is the self-cleaning step: simulations of MPW aluminum lap joints estimate jet velocities of about 1000–2000 m/s, and the jet's composition follows density difference, so in Al/Cu and Al/Ni pairs it consists mainly of the lower-density aluminum.[6](https://www.jstage.jst.go.jp/article/matertrans/52/5/52_L-MZ201128/_pdf) Jetting is not necessarily a continuous stream; it can also occur as a cloud of particles of spalled oxide and dispersed metal that must leave the joining zone before the surfaces touch.[7](https://www.mdpi.com/2075-4701/10/8/1108)\n\nCollision pressures on the order of GPa exceed the Hugoniot Elastic Limit, so the solid metal flows like a fluid.[8](https://www.jstage.jst.go.jp/article/matertrans/62/8/62_L-M2021828/_pdf/-char/en) Despite the \"solid-state\" label, temperatures at the interface can locally exceed the pressure-elevated melting points (about 2600 K on the steel side and 1730 K on the aluminum side in one MPW study), while the base metal 40 µm away barely heats; the thin intermetallic-rich layer forms by rapid solidification of this local melt.[8](https://www.jstage.jst.go.jp/article/matertrans/62/8/62_L-M2021828/_pdf/-char/en) The characteristic wavy interface has been explained by continuous hump formation ahead of the collision point, a mechanism proposed by A. S. Bahrani, T. J. Black, and Bernard Crossland in 1967,[9](https://doi.org/10.1098/rspa.1967.0010) and by competing pictures including [Kelvin–Helmholtz instability](https://www.edgepedia.org/kelvin-helmholtz-instability) and fluid analogy.[10](https://www.osti.gov/servlets/purl/1490321) Ambient gas matters: lower gas density gives higher weld strength, and a minimum jet velocity of around 2000 m/s appears necessary for a joint regardless of gas.[11](https://eldorado.tu-dortmund.de/server/api/core/bitstreams/1ef46860-679b-4d20-b06d-aea7bffbace7/content) At the finest scale, bonding strength tracks local effective pressure times local surface exposure, capped by the base metal's flow stress; localized contact pressures near 5 GPa produced the strongest bonds in microparticle impact experiments.[12](https://par.nsf.gov/servlets/purl/10579998)\n\n## How it is done\n\nAcross variants, practitioners work within a [weldability](https://www.edgepedia.org/weldability) window in velocity–angle space, bounded by upper and lower welding-velocity limits, a critical angle for jet formation, and a transition velocity from straight to wavy interfaces; the map shifts with material properties.[1](https://www.mdpi.com/2075-4701/9/2/144) The evolution of the lower boundary criterion remains an active topic.[13](https://doi.org/10.1016/j.jmatprotec.2011.08.017)\n\n## Variants\n\n**Explosive welding** detonates a layer of explosive against the flyer across a standoff gap. The loading ratio (explosive mass to flyer weight) sets the collision velocity, dynamic bend angle, and jet formation; too much or too little gives incomplete bonding or interface degradation.[14](https://link.springer.com/article/10.1134/S0010508226700267)\n\n**Magnetic pulse welding** discharges a capacitor bank through a coil, using transient current pulses above 50,000 amps to launch a high-conductivity flyer; coils limit practical flyer thickness to roughly 2 mm.[2](https://mse.osu.edu/sites/default/files/uploads/mrs_bulletin_aug_2019_vfaw_article.pdf)\n\n**VFAW** vaporizes a consumable aluminum foil actuator, 0.0254–0.127 mm thick, in contact with the flyer; the vapor's expansion accelerates the flyer across a standoff. Vaporization uses 3–20 kV pulses at 50–300 kA within under 20 µs, launching flyers at 200–1500 m/s.[15](https://www.nature.com/articles/s41598-024-74077-1)\n\n**Laser impact welding** drives the flyer with a pulsed laser, typically about 10 ns at 1064 nm, with about 1 J the minimum for millimeter-scale spots, using a confinement layer and an ablative layer; flyer velocity follows a Gurney-model relation.[16](https://mdpi-res.com/d_attachment/metals/metals-10-01444/article_deploy/metals-10-01444-v2.pdf?version=1604408296) The variant was demonstrated for aluminum to titanium by Huimin Wang and colleagues in 2016 in the Journal of Laser Applications.[17](https://doi.org/10.2351/1.4946887) Mengyuan Gong and colleagues reported standoff-free VFAW, which removes the gap requirement between actuator and flyer, in 2024 in the Journal of Manufacturing Processes.[18](https://doi.org/10.1016/j.jmapro.2024.09.051)\n\n## Origin\n\nDuring the First World War it was well known that a bullet or shrapnel could stick to metal surfaces it struck.[19](https://www.tandfonline.com/doi/abs/10.1179/mtlr.1970.15.1.79) [Detonation](https://www.edgepedia.org/detonation) impulses produced brass welds with no melting at the interface, and the method was termed solid-state welding.[20](https://bibliotekanauki.pl/articles/64182045.pdf) Attribution is disputed: Crossland and Williams write that explosive welding \"was probably discovered by chance\",[19](https://www.tandfonline.com/doi/abs/10.1179/mtlr.1970.15.1.79) while other accounts credit accidental discovery by ordnance specialists during World War I.[21](https://onlinelibrary.wiley.com/doi/pdf/10.1002/9781394331925.ch8) • [21](https://onlinelibrary.wiley.com/doi/pdf/10.1002/9781394331925.ch8) Philipchuk's DuPont team commercialized the process as Detaclad, which supplied coin blanks to the Denver and Philadelphia mints; DMC purchased Detaclad in 1996.[20](https://bibliotekanauki.pl/articles/64182045.pdf)\n\nThe physics came from adjacent work. William A. Allen, Joe M. Mapes, and Wesley G. Wilson reported rippling and adhesion from oblique cylinder impact in 1954 in the [Journal of Applied Physics](https://www.edgepedia.org/journal-of-applied-physics),[22](https://doi.org/10.1063/1.1721710) and jetting theory rests on the lined-cavity collapse analysis by [Garrett Birkhoff](https://www.edgepedia.org/garrett-birkhoff) and colleagues in 1948, also in the Journal of Applied Physics.[23](https://doi.org/10.1063/1.1698173) George R. Cowan and Arnold H. Holtzman analyzed flow configurations in explosively bonded plates in 1963 in the Journal of Applied Physics,[24](https://doi.org/10.1063/1.1729565) and Cowan, O. R. Bergmann, and A. H. Holtzman published a wave-formation mechanism in 1971 in Metallurgical Transactions.[25](https://doi.org/10.1007/bf02814967) Sources disagree on when electromagnetic pulse welding began, in the 1960s[11](https://eldorado.tu-dortmund.de/server/api/core/bitstreams/1ef46860-679b-4d20-b06d-aea7bffbace7/content) or with a 1970 proposal.[26](https://mdpi-res.com/d_attachment/jmmp/jmmp-05-00066/article_deploy/jmmp-05-00066.pdf?version=1624508857) A U.S. LIW patent was filed.[1](https://www.mdpi.com/2075-4701/9/2/144)\n\n## Applications\n\nEXW is used mainly for large-scale cladding.[7](https://www.mdpi.com/2075-4701/10/8/1108) VFAW's main application is automotive spot joining: it was demonstrated for 18 dissimilar combinations of automotive steel, aluminum, and magnesium alloys, with 8 combinations reaching 90° peel strength above 30 N/mm or lap-shear strength exceeding a base metal.[5](https://www.osti.gov/servlets/purl/1416747) VFAW spot joints in steel to aluminum showed 19.87% higher normalized lap-shear strength than self-pierce riveting.[4](https://www.sciencedirect.com/science/article/abs/pii/S0142112324006546) A VFAW aluminum joint with 21,000 N static strength sustained about 3000 N at 1,000,000 cycles, against 1100 N for a 6000 N resistance spot weld.[2](https://mse.osu.edu/sites/default/files/uploads/mrs_bulletin_aug_2019_vfaw_article.pdf) Kapil and colleagues showed VFAW spot welding uses less than one third of the energy of resistance spot welding.[3](https://www.sciencedirect.com/science/article/abs/pii/S1526612518311083) Ti–Cu VFAW welds with shear strength above 45 MPa formed even without deep waves, indicating jetting rather than waviness is the better success criterion.[10](https://www.osti.gov/servlets/purl/1490321) LIW targets battery electrodes, medical devices such as aluminum–titanium pacemaker electrodes, anti-corrosion coatings, and semiconductor heat-dissipation layers.[16](https://mdpi-res.com/d_attachment/metals/metals-10-01444/article_deploy/metals-10-01444-v2.pdf?version=1604408296)\n\n## Limitations and alternatives\n\nExcessive flyer kinetic energy causes melting and continuous intermetallics at the interface, so there is an upper energy limit; very high impact pressure can spall the flyer or target.[1](https://www.mdpi.com/2075-4701/9/2/144) Brittle intermetallic compound formation is the recurring problem for high-strength, difficult-to-weld pairs, and heat treatment can lower hardness and brittleness in explosively welded material.[21](https://onlinelibrary.wiley.com/doi/pdf/10.1002/9781394331925.ch8) MPW commercialization is hindered by limited coil longevity and constraints on flyer conductivity and thickness, whereas the consumable VFAW foil avoids tool-fatigue concerns.[3](https://www.sciencedirect.com/science/article/abs/pii/S1526612518311083) EXW requires an isolated production environment because of safety and noise, operator protection, licensing, and simple flat or cylindrical geometries.[3](https://www.sciencedirect.com/science/article/abs/pii/S1526612518311083) • [20](https://bibliotekanauki.pl/articles/64182045.pdf)\n\n## References\n\n1. [High-Velocity Impact Welding Process: A Review (Wang & Wang, Metals 2019)](https://www.mdpi.com/2075-4701/9/2/144)\n2. [Joining of dissimilar lightweight materials (MRS Bulletin, Aug 2019)](https://mse.osu.edu/sites/default/files/uploads/mrs_bulletin_aug_2019_vfaw_article.pdf)\n3. [Civilized explosive welding: Impact welding of thick aluminum to steel plates without explosives (Journal of Manufacturing Processes)](https://www.sciencedirect.com/science/article/abs/pii/S1526612518311083)\n4. [The mechanical performance of the automotive Fe-Al dissimilar spot impact weld: In comparison to the self pierced riveted joint (International Journal of Fatigue, 2024)](https://www.sciencedirect.com/science/article/abs/pii/S0142112324006546)\n5. [Final Technical Report: VFAW for dissimilar-metal joining (DOE OSTI)](https://www.osti.gov/servlets/purl/1416747)\n6. [Metal jet emission and weld interface formation in impact welding (Materials Transactions, 2011, Kakizaki et al.)](https://www.jstage.jst.go.jp/article/matertrans/52/5/52_L-MZ201128/_pdf)\n7. [Particle Ejection by Jetting and Related Effects in Impact Welding Processes (Metals, 2020)](https://www.mdpi.com/2075-4701/10/8/1108)\n8. [Experimental and Numerical Analyses of Wavy Interface Formation and Local Melting Phenomena at the Magnetic Pulse Welded Al/Fe Joint Interface (Materials Transactions, 2021)](https://www.jstage.jst.go.jp/article/matertrans/62/8/62_L-M2021828/_pdf/-char/en)\n9. [A. S. Bahrani, T. J. Black, Bernard Crossland (1967). The mechanics of wave formation in explosive welding. Proceedings of the Royal Society of London A Mathematical and Physical Sciences.](https://doi.org/10.1098/rspa.1967.0010)\n10. [A robust process-structure model for predicting the joint interface structure in impact welding (OSTI)](https://www.osti.gov/servlets/purl/1490321)\n11. [Identification of additional process parameters for impact welding and their influence on the process (TU Dortmund)](https://eldorado.tu-dortmund.de/server/api/core/bitstreams/1ef46860-679b-4d20-b06d-aea7bffbace7/content)\n12. [Strength gradient in impact-induced metallic bonding](https://par.nsf.gov/servlets/purl/10579998)\n13. [V.I. Lysak, S.V. Kuzmin (2011). Lower boundary in metal explosive welding. Evolution of ideas. Journal of Materials Processing Technology.](https://doi.org/10.1016/j.jmatprotec.2011.08.017)\n14. [The Effect of Loading Ratio on the Interface Morphology in Explosive Welding: A Review (Combustion, Explosion, and Shock Waves)](https://link.springer.com/article/10.1134/S0010508226700267)\n15. [Interfacial energy conversion mechanism between 3003 aluminum alloy and 321 stainless steel in VFAW (Scientific Reports, 2024)](https://www.nature.com/articles/s41598-024-74077-1)\n16. [Research Status and Prospect of Laser Impact Welding (Metals 2020)](https://mdpi-res.com/d_attachment/metals/metals-10-01444/article_deploy/metals-10-01444-v2.pdf?version=1604408296)\n17. [Huimin Wang and colleagues (2016). Laser impact welding application in joining aluminum to titanium. Journal of Laser Applications.](https://doi.org/10.2351/1.4946887)\n18. [Mengyuan Gong and colleagues (2024). Standoff-free vaporizing foil actuator welding: Process principle, experimental validation, and mechanisms analysis. Journal of Manufacturing Processes.](https://doi.org/10.1016/j.jmapro.2024.09.051)\n19. [Explosive Welding, B. Crossland & J. D. Williams, Metallurgical Reviews 15(1), 79-100, 1970](https://www.tandfonline.com/doi/abs/10.1179/mtlr.1970.15.1.79)\n20. [Explosion Welding of Metals: Physical Aspects and Applications](https://bibliotekanauki.pl/articles/64182045.pdf)\n21. [Microstructural Control and Heat Treatment Effects in Explosion Welding (Wiley book chapter)](https://onlinelibrary.wiley.com/doi/pdf/10.1002/9781394331925.ch8)\n22. [William A. Allen, Joe M. Mapes, Wesley G. Wilson (1954). An Effect Produced by Oblique Impact of a Cylinder on a Thin Target. Journal of Applied Physics.](https://doi.org/10.1063/1.1721710)\n23. [Garrett Birkhoff and colleagues (1948). Explosives with Lined Cavities. Journal of Applied Physics.](https://doi.org/10.1063/1.1698173)\n24. [George R. Cowan, Arnold H. Holtzman (1963). Flow Configurations in Colliding Plates: Explosive Bonding. Journal of Applied Physics.](https://doi.org/10.1063/1.1729565)\n25. [G. R. Cowan, O. R. Bergmann, A. H. Holtzman (1971). Mechanism of bond zone wave formation in explosion-clad metals. Metallurgical Transactions.](https://doi.org/10.1007/bf02814967)\n26. [Experimental and Numerical Investigations into Magnetic Pulse Welding of Aluminum Alloy 6016 to Hardened Steel 22MnB5 (Journal of Manufacturing and Materials Processing)](https://mdpi-res.com/d_attachment/jmmp/jmmp-05-00066/article_deploy/jmmp-05-00066.pdf?version=1624508857)\n\n---\n*Topic: Encyclopedia › Technology and the built world › Engineering and manufacturing › Manufacturing processes and fabrication › Welding, soldering, and joining*\n\n*Initially written Sep 29, 2026 · Edited: Oct 15, 2026*\n\n*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*\n\nLicense: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license\n", "same_as": [], "url": "https://www.edgepedia.org/impact-welding", "markdown_url": "https://www.edgepedia.org/impact-welding.md", "license": { "name": "Edgepedia Community License 1.0", "url": "https://www.edgepedia.org/edgepedia/license", "summary": "Free with credit, commercial use included. AI training is open to everyone. For other uses, organizations over USD 100M in revenue or 100M monthly users license separately.", "spdx": "LicenseRef-Edgepedia-Community-1.0" }, "credit": "\"Impact welding\", Edgepedia (EdgeChat), https://www.edgepedia.org/impact-welding. Edgepedia Community License 1.0.", "credit_md": "\"[Impact welding](https://www.edgepedia.org/impact-welding)\", Edgepedia (EdgeChat), [https://www.edgepedia.org/impact-welding](https://www.edgepedia.org/impact-welding). [Edgepedia Community License 1.0](https://www.edgepedia.org/edgepedia/license).", "credit_html": "\"Impact welding\", Edgepedia (EdgeChat), https://www.edgepedia.org/impact-welding. Edgepedia Community License 1.0.", "speakable": "Impact welding is a solid-state joining method that bonds similar or dissimilar metals by driving a flyer plate into a target at several hundred meters per second." }