OBRABOTKAMETALLOV Vol. 25 No. 3 2023 technology In general, fig. 7 shows a monotonous increase in both parameters (surface extend Y and maximum pressure p), which will increase the bond strength. This conclusion is consistent with the results of experimental studies of the rolling process of aluminum and aluminum alloys [4, 6, 7, 10], where an increase in reductions led to an increase in the bond strength between materials. Based on the obtained computer simulation data, it follows that the maximum bond strength will be provided by the technological rolling route: reduction ratio in the 1st pass – 45 %; reduction ratio in the 2nd pass – 50 % (the total reduction ratio reaches 75 %). This conclusion is verified by shear tests of the composite obtained through the suggested route. The bond strength reached 67 MPa, which is 1.5 times higher than the primary bond strength obtained by the first pass of rolling. Thus, the proposed approach reflects the qualitative dependence of the bond strength on the technological factors of rolling. The problem with the proposed approach for investigating the bond formation between dissimilar materials lies in the great difficulty in establishing the threshold surface extend Y´, which should be determined for each newly developed composite. In this regard, the direction of future research should be related to the development of new models of the rolling processes of laminated composites and the development of more reliable criteria for the bond formation between dissimilar materials. Conclusions In this work, simulation of the rolling process of the laminated composite “AMg3/D16/AMg3” was performed, and stress-strain state parameters affecting the bond formation between layers were estimated. It was found that the deformation is distributed nonuniformly over the thickness of the layers during rolling: the outer layers flow more intensively than the middle layer. However, the maximum effective strain scatter of 12 % in the cross section was observed after the highest rolling reduction of 75 %. This allows us to make an assumption about deformation uniformity in the first approximation for analytical calculations. Additionally, a relationship has been established between the onset of bond formation and the contact surface extend and pressure. In the case of rolling at a reduction of 30 %, the contact surface extend reaches a threshold value close to the exit from the deformation zone, while the normal pressures drop sharply, which results in a lack of bonding. In the case of rolling with a reduction of 45 %, the contact surface extend reaches the threshold value at a relative length of the deformation zone of 0.42. In the remaining area of the deformation zone, a relative normal pressure increases from 1.6 to 1.97, which is sufficient to form primary bonding between AMg3 and D16 alloys. References 1. Williams J.C., Starke E.A. Progress in structural materials for aerospace systems. Acta Materialia, 2003, vol. 51, pp. 5775–5799. DOI: 10.1016/j.actamat.2003.08.023. 2. Ghalehbandi S.M., Malaki M., Gupta M. Accumulative roll bonding – A Review. Applied Sciences, 2019, vol. 9, p. 3627. DOI: 10.3390/app9173627. 3. Salikhyanov D. Contact mechanism between dissimilar materials under plastic deformation. Comptes Rendus Mecanique, 2019, vol. 347, pp. 588–600. DOI: 10.1016/j.crme.2019.07.002. 4. Jamaati R., Toroghinejad M.R. Cold roll bonding bond strengths: review. Materials Science and Technology, 2011, vol. 27, iss. 7, pp. 1101–1108. DOI: 10.1179/026708310X12815992418256. 5. Li L., Nagai K., Yin F. Progress in cold roll bonding of metals. Science and Technology of Advanced Materials, 2008, vol. 9, p. 023001. DOI: 10.1088/1468-6996/9/2/023001. 6. Jamaati R., Toroghinejad M.R. The role of surface preparation parameters on cold roll bonding of aluminum strips. Journal of Materials Engineering and Performance, 2011, vol. 20, pp. 191–197. DOI: 10.1007/s11665-010-9664-7. 7. Madaah-Hosseini H.R., Kokabi A.H. Cold roll bonding of 5754-aluminum strips. Materials Science and Engineering A, 2002, vol. 335, pp. 186–190. DOI: 10.1016/S0921-5093(01)01925-6. 8. Heydari Vini M., Sedighi M., Mondali M. Investigation of bonding behavior of AA1050/AA5083 bimetallic laminates by roll bonding technique. Transactions of the Indian Institute of Metals, 2018, vol. 71, iss. 9, pp. 2089– 2094. DOI: 10.1007/s12666-017-1058-1. 9. Heydari Vini M., Daneshmand S., Forooghi M. Roll bonding properties ofAl/Cu bimetallic laminates fabricated by the roll bonding technique. Technologies, 2017, vol. 5 (2), p. 32. DOI: 10.3390/technologies5020032.
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