Kompozit JSC, Korolev, Russia:

D. N. Makhina, Junior Researcher, e-mail: loskutovadn@gmail.com
V. N. Denisov, Senior Researcher, Candidate of Technical Sciences

A. S. Klyatskin, Head of the Welding and Soldering Department

National University of Science and Technology MISiS, Moscow, Russia:
S. A. Nikulin, Head of the Department of Metal Science and Physics of Strength, Doctor of Technical Sciences

Bimetals on the base of aluminum alloys and stainless steel are extensively used in the rocket and space, shipbuilding, automobile industries. Depending on the requirements and practical applications of an aluminum alloy-steel bimetal, critical parts are manufactured preferably by solid-state welding. A research of a structure and bond strength of an aluminum alloy connection (Grade AMg6) with stainless steel (Grade 12Kh18N10T) with an aluminum interlayer (AD1) manufactured by diffusion welding under hot isostatic pressing conditions (HIP) has been performed. The research includes an influence of the temperature on the structure by scanning electron microscopy, electron microprobe analysis, mechanical tests and fractography methods. The obtaining of the bimetal was performed in a laboratory gasostat in the temperature range from 530 to 570 ^oC. The research results of the transition area structure, on the border between steel and the interlayer, are shown. It was revealed that the intermetalic layer based on ferrum, chromium, nickel and aluminium is formed in the transition area on the border between steel 12Kh18N10T and aluminum AD1. The structure of the intermetalic layer defines mechanical properties of the bimetal (aluminum alloy AMg6 – steel 12Kh18N10T). It was found that under the HIP temperature of the bimetal, 540 ^oC, on the border between steel and the interlayer a discontinuous layer consisted of separate particles of the intermetalic metal has formed. The thickness of the layer is 3 μm. In addition to this, the values of ultimate tensile strength and ultimate bending strength of the bimetal connection were 157–205 MPa and 282–352 MPa accordingly.

1. Oryshchenko A. S., Osokin E. P., Pavlova V. I., Zykov S. A. Bimetallic ferroaluminium compositions for vessel hulls. Avtomaticheskaya svarka. 2009. No. 10. pp. 43–47.
2. Gurevich L. M., Pronichev D. V., Trudov A. F., Trykov Yu. P., Trunov M. D. Understanding how different regimes of explosion welding and heat treatment impact the structure and properties of the AD1/steel ST3 bimetal. Izvestiya VolGTU. 2014. No. 9, Vol. 9. pp. 17–21.
3. Yokoyama T. Impact performance of friction welded butt joints between 6061-T6 aluminium alloy and type 304 stainless steel. Materials Science and Technology. 2003. Vol. 19, Iss. 10. pp. 1418–1426.
4. Sivaprasad K., Muralimohan C. H., Haribabu S., Hariprasada Reddy Y., Muthupandi V. Joining of AISI 1040 Steel to 6082-T6 Aluminium Alloy by Friction welding. Journal of Advances in Mechanical Engineering and Science. 2015. Vol. 1, Iss. 1. pp. 57–64.
5. Kimura M., Kusaka M., Kaizu K., Nakata K., Nagatsuka K. Friction wel ding technique and joint properties of thin-walled pipe friction-welded joint between type 6063 aluminum alloy and AISI 304 austenitic stainless steel. The International Journal of Advanced Manufacturing Technology. 2016. Vol. 82. pp. 489–499.
6. Aryshnskii E. V., Bazhin V. Yu., Kawalla R. Strategy of refining the structure of aluminummagnesium alloys by complex microalloying with transition elements during casting and subsequent thermomechanical processing. Nonferrous Metals. 2019. No. 1. Р. 28–32.
7. Diffusion welding of materials. Reference book. Ed. by N. F. Kazakov. Moscow : Mashinostroenie, 1981.
8. Springer H., Kostka A., dos Santos J. F., Raabe D. Influence of intermetallic phases and Kirkendall-porosity on the mechanical properties of joints between steel and aluminium alloys. Materials Science and Engineering: A. 2011. Vol. 528. pp. 4630–4642.
9. Butrim V., Beresnev A., Denisov V., Klyatskin A., Medvedev D., Makhina D. Experience in HIP diffusion welding of dissimilar metals and alloys. HIP17 — 12^th International conference on Hot Isostatic Pressing 2017, Sydney, Australia, 5–8 December 2017. Materials Research Proceeding. 2019. Vol. 10. pp. 65–72.
10. Makhina D. N., Denisov V. N., Perminova Yu. S., Butrim V. N., Niku lin S. A. The structure and mechanical properties of molybdenum/steel bimetal produced by hot isostatic pressing. Deformatsiya i razrushenie materialov. 2019. No. 5. pp. 27–32.
11. Ord s N., Samaniego F., Iturriza I., G mez A., Escudero C. et al. Mechanical and microstructural characterization of HIP joints of a simplified prototype of the ITER NHF First Wall Panel. Fusion Engineering and Design. 2017. Vol. 124. pp. 999–1003.
12. Sokolova T. V. Investigating the interface region in the bimetal EP838 austenitic steel/aluminium. Vestnik Rossiyskogo universiteta druzhby narodov. Seriya: Inzhenernye issledovaniya. 2005. No. 1. pp. 74–79.
13. Hongxin Shi, Shuang Qiao, Ranfeng Qiu, Xiaojiao Zhang, Hua Yu. Effect of Welding Time on the Joining Phenomena of Diffusion Welded Joint between Aluminum Alloy and Stainless Steel. Materials and Manufacturing Processes. 2012. Vol. 27. pp. 1366–1369.
14. GOST 1497–84. Metals. Methods of tension test. Introduced: 01.01.1986.
15. GOST 14019–2003. Metallic materials. Bend test method. Introduced: 01.09.2004.