621.721

aluminum, friction stir welding, post-weld treatment, explosive hardening.

The study describes the theoretical background and technological aspects of the post-weld explosive treatment of high-strength aluminum alloy FSW joints. Although FSW allows to effective join high-strength aluminum alloys, the heat generated during the process causes undesirable changes in the strengthening phase, giving a joint efficiency of about 80%. The load-carrying capabilities of these joints can be increased via post-weld treatment (e.g. shot peening, laser shock peening). The new, potential post-weld treatment that is presented in this paper is based on the affection of the welded joint by a shock wave generated during the detonation of explosive material. Such post-weld explosive treatment would result in the hardening of the low-hardness zone, which often determines the mechanical properties of precipitation-hardened aluminum alloy FSW joints. Studies show that explosive welding of annealed aluminum alloys increases their microhardness by about 25% as the result of a high-velocity collision. If a similar effect can be achieved in explosive hardening, the microhardness of the low-hardness zone will increase entailing an improvement of entire joint mechanical properties. The variety of explosives materials used in metalworking (covering the values of detonation velocity from about 2000 m/s to 8000 m/s) and different systems for shock-wave affection gives many technological possibilities. In this work are discussed two different explosive hardening systems: with direct placement of explosive material on a treated welded plate and with an additional driven plate, which provides a higher pressure impulse. Considering that affecting of high amplitude shock wave introduces defects into the structure and decreases residual stresses in the welded joints, the application of an appropriate technological system creates a potential for improving the load-carrying capacities of discussed joints, especially in a condition of cyclic loading. 

1. Çam G., Mistikoglu S.: Recent Developments in Friction Stir Welding of Al-Alloys, Journal of Materials Engineering and Performance. 2014. 23. Р. 1936–1953.
2. Kosturek R., Torzewski J., Wachowski M., Śnieżek L.: Effect of Welding Parameters on Mechanical Properties and Microstructure of Friction Stir Welded AA7075-T651 Aluminum Alloy Butt Joints, Materials.,2022, 15, 5950.
3. Kosturek R., Torzewski J., Joska Z., Wachowski M., Śnieżek L.: The influence of tool rotation speed on the low-cycle fatigue behavior of AA2519-T62 friction stir welded butt joints, Engineering Failure Analysis, 2022, 142, 106756.
4. Xu W., Liu J.H., Chen D.L., Luan G.H.: Low-cycle fatigue of a friction stir welded 2219-T62 aluminum alloy at different welding parameters and cooling conditions. Int. J. Adv. Manuf. Technol. 2014. 74.
   Р. 209–218.
5. Suckow T., Völkers S., Bütev Öcal E., Grass M., Böhm S., Groche P.: Effect of Shortened Post Weld Heat Treatment on the Laser Welded AA7075 Alloy, Metals, 2022,12, 393.
6. Kosturek R., Śnieżek L., Wachowski M., Torzewski J.: The Influence of Post-Weld Heat Treatment on the Microstructure and Fatigue Properties of Sc-Modified AA2519 Friction Stir-Welded Joint, Materials, 12, 4, 2019, 1–17.
7. Babul W.: Odkształcanie metali wybuchem, Wydawnictwa Naukowo-Techniczne, Warszawa 1980.
8. Petushkov V.G., Kudinov V.M., Berezina N.V. Mekhanizm pereraspredeleniya ostatochnykh napryazheniy pri vzryvnom nagruzhenii, Avtomaticheskaya svarka. 1974, Nо. 3. Р. 37–39.
9. Trufyakov V. I. Ustalost' svarnykh soyedineniy. Naukova dumka. Kiev, 1973.
10. Najwer M., Niesłony P.: Ocena mikrotwardości oraz własności wytrzymałościowych trimetalu AA2519-AA1050-TI6AL4V po różnych obróbkach cieplnych. Przegląd Spawalnictwa. 2016. 88. 4. Р. 16–18.
11. Nowaczewski J., Kita M., Świeczak J., Rudnicki J.: Obróbka wybuchowa i cieplno-chemiczna wielowarstwowych kompozytów metalicznych. Materiały Wysokoenergetyczne. 2011. 3. Р. 84–89.
12. Maranda A.: Przemysłowe materiały wybuchowe, Wyd. Wojskowa Akademia Techniczna, Warszawa 2010.
13. Kosturek R, Maranda A., Senderowski C., Zasada D.: Badania nad zastosowaniem zgrzewania wybuchowego do uzyskania bimetalicznych blach z udziałem staliwa Hadfielda, Materiały Wysokoenergetyczne. High-Energetic Materials. 2016. 8. Р. 91−102.
14. H. S. F. L. Carvalho, Gustavo, Ivan Galvão, Ricardo Mendes, Rui M. Leal, and Altino Loureiro, Aluminum-to-Steel Cladding by Explosive Welding, Metals, 10, 8, 2020.
15. Kosturek R., Wachowski M., Śnieżek L., Gloc M.: The Influence of the Post-Weld Heat Treatment on the Microstructure of Inconel 625/Carbon Steel Bimetal Joint Obtained by Explosive Welding, Metals, 9, 2, 2019.
16. Zhang, F. & Lv, B. & Wang, T.S. & Zheng, Chunlei & Zhang, Maofeng & Luo, H. & Liu, H. & Xu, A., Explosion hardening of Hadfield steel crossing, Materials Science and Technology. 26. 2012. Р. 223–229.
17. Neu,C. E., Properties of Shock Hardened 7050 Aluminum Alloy, Naval Air Development Center Warminster Pa Aircraft And Crew Systems Technology Directorate, 1981.
18. Yansong Guo, Qiang Zhou, Chun Ran, Rui Liu, Ali Arab, Yeping Ren, Pengwan Chen, Shock-induced large-depth gradient microstructure in commercial pure titanium subjected to explosive hardening. Materials & Design. Volume 213. 2022.
19. Chavez D. E., Harry H. H., W. Olinger B. W.: An Environmentally Friendly Baratol Replacement for Plane Wave Generator Applications, Journal of Energetic Materials, 2014, 32:2, 128-13.

1. Çam G., Mistikoglu S.: Recent Developments in Friction Stir Welding of Al-Alloys, Journal of Materials Engineering and Performance. 2014. 23. Р. 1936–1953.
2. Kosturek R., Torzewski J., Wachowski M., Śnieżek L.: Effect of Welding Parameters on Mechanical Properties and Microstructure of Friction Stir Welded AA7075-T651 Aluminum Alloy Butt Joints, Materials.,2022, 15, 5950.
3. Kosturek R., Torzewski J., Joska Z., Wachowski M., Śnieżek L.: The influence of tool rotation speed on the low-cycle fatigue behavior of AA2519-T62 friction stir welded butt joints, Engineering Failure Analysis, 2022, 142, 106756.
4. Xu W., Liu J.H., Chen D.L., Luan G.H.: Low-cycle fatigue of a friction stir welded 2219-T62 aluminum alloy at different welding parameters and cooling conditions. Int. J. Adv. Manuf. Technol. 2014. 74.
   Р. 209–218.
5. Suckow T., Völkers S., Bütev Öcal E., Grass M., Böhm S., Groche P.: Effect of Shortened Post Weld Heat Treatment on the Laser Welded AA7075 Alloy, Metals, 2022,12, 393.
6. Kosturek R., Śnieżek L., Wachowski M., Torzewski J.: The Influence of Post-Weld Heat Treatment on the Microstructure and Fatigue Properties of Sc-Modified AA2519 Friction Stir-Welded Joint, Materials, 12, 4, 2019, 1–17.
7. Babul W.: Odkształcanie metali wybuchem, Wydawnictwa Naukowo-Techniczne, Warszawa 1980.
8. Petushkov V.G., Kudinov V.M., Berezina N.V. Mekhanizm pereraspredeleniya ostatochnykh napryazheniy pri vzryvnom nagruzhenii, Avtomaticheskaya svarka. 1974, Nо. 3. Р. 37–39.
9. Trufyakov V. I. Ustalost' svarnykh soyedineniy. Naukova dumka. Kiev, 1973.
10. Najwer M., Niesłony P.: Ocena mikrotwardości oraz własności wytrzymałościowych trimetalu AA2519-AA1050-TI6AL4V po różnych obróbkach cieplnych. Przegląd Spawalnictwa. 2016. 88. 4. Р. 16–18.
11. Nowaczewski J., Kita M., Świeczak J., Rudnicki J.: Obróbka wybuchowa i cieplno-chemiczna wielowarstwowych kompozytów metalicznych. Materiały Wysokoenergetyczne. 2011. 3. Р. 84–89.
12. Maranda A.: Przemysłowe materiały wybuchowe, Wyd. Wojskowa Akademia Techniczna, Warszawa 2010.
13. Kosturek R, Maranda A., Senderowski C., Zasada D.: Badania nad zastosowaniem zgrzewania wybuchowego do uzyskania bimetalicznych blach z udziałem staliwa Hadfielda, Materiały Wysokoenergetyczne. High-Energetic Materials. 2016. 8. Р. 91−102.
14. H. S. F. L. Carvalho, Gustavo, Ivan Galvão, Ricardo Mendes, Rui M. Leal, and Altino Loureiro, Aluminum-to-Steel Cladding by Explosive Welding, Metals, 10, 8, 2020.
15. Kosturek R., Wachowski M., Śnieżek L., Gloc M.: The Influence of the Post-Weld Heat Treatment on the Microstructure of Inconel 625/Carbon Steel Bimetal Joint Obtained by Explosive Welding, Metals, 9, 2, 2019.
16. Zhang, F. & Lv, B. & Wang, T.S. & Zheng, Chunlei & Zhang, Maofeng & Luo, H. & Liu, H. & Xu, A., Explosion hardening of Hadfield steel crossing, Materials Science and Technology. 26. 2012. Р. 223–229.
17. Neu,C. E., Properties of Shock Hardened 7050 Aluminum Alloy, Naval Air Development Center Warminster Pa Aircraft And Crew Systems Technology Directorate, 1981.
18. Yansong Guo, Qiang Zhou, Chun Ran, Rui Liu, Ali Arab, Yeping Ren, Pengwan Chen, Shock-induced large-depth gradient microstructure in commercial pure titanium subjected to explosive hardening. Materials & Design. Volume 213. 2022.
19. Chavez D. E., Harry H. H., W. Olinger B. W.: An Environmentally Friendly Baratol Replacement for Plane Wave Generator Applications, Journal of Energetic Materials, 2014, 32:2, 128-13.