A7

Working Group A | Metallurgical joint

 
 
a7_spp1640

Roll bonding materials with different yield strengths – An analysis of the joining mechanism and modeling new manufacturing procedures

Prof. Dr.-Ing. Gerhard Hirt, Aachen University
Dr.-Ing. Markus Bambach, Aachen University

 
 

Abstract:

Plating is a process to join two or more metals permanently using pressure and/or temperature. Therewith it is possible to combine different material characteristics for optimal performance properties.

The most common industrial method is roll bonding. Therefor pressure is applied during a rolling process.

The metallophysical phenomena, that are responsible for the development of the bond, are not completely clear jet. In contrast the process has been used in the industry for decades, e.g. for coinage and the production of bimetallic switches.

The two finished funding phases addressed hot roll bonding of aluminum slabs. The developed basic experiment enables the user to reproduce the conditions found in the roll gap, which lead to the bonding. Based on the results, a FE-Modell including a user Subroutine was developed, which is able to simulate the interactions between the layers.

 
 
Concept sketch of the conductive heating unit for the adjustment of the flow stresses of Ni99.2 and Al99.5
Concept sketch of the conductive heating unit for the adjustment of the flow stresses of Ni99.2 and Al99.5
 
 

This third funding phase addresses cold roll bonding of thin metallic coils. In this case, all combination are critical, in which materials with different strengths and initial heights are roll bonded.

Exemplary, cold roll bonding of a thin and harder nickel layer (Ni99.2) on a thicker and softer aluminum layer (Al99.5) is investigated. E.g., this material combination is used in battery housings.

On the one hand, it is necessary to apply a large true strain for a high join strength (green strength), which is able to prevent the separation of the composite material during further processing.

On the other hand, the large difference in strength leads to great differences in elongation. This leads to large tensile stress in the hard and thin layer. Periodic fluctuations in thickness can occur and finally lead to cracks.

Goal of the third funding phase is to find answers for the described problems.

To reach this goal, it is necessary to expand the FE-Modell for cold roll bonding and to try a heating system that is able to align the flow stresses of the materials.

Furthermore, chemical and mechanical activation of the surface and its influence on the join strength is tested.

 
 

Publications:

2018   
  A New Coupled Thermal-Stress FE-Model for Investigating the Influence of Non-Isothermal Conditions on Bond Strength and Bonding Status of the First Pass in Roll Bonding Liu, Z.; Kraemer, A.; Karhausen, K. F.; Aretz, H.; Teller, M.; Hirt, G.
In: Key Engineering Materials Vol. 767 2018, S. 301-308
2016   
  Untersuchungen zur Verbindungsentstehung beim Warmwalzplattieren von Aluminium Karhausen, K. F.; Pietryga, M.; Janssen, J.; Lohmar, J.; Hirt, G.
In: Tagungsband 31. ASK Umformtechnik, 2016, pp. 207–216
  A new FE-Model for the investigation of bond formation and failure in rolling processes Pietryga, M.; Lohmar, J.; Hirt, G.
Materials Science Forum Vol. 854, 2016, pp. 152–157
2015   
  Finite Element Analysis of Manufacturing Micro Lubrication Pockets in High Strength Steels by Hot Micro-Coining Szurdak, A.; Hirt G.
steel research int. 86, 2015, No. 3, pp. 257–265
  Production of Clad Steel Strips by Twin-Roll Strip Casting Vidoni, M.; Ackermann, R.; Richter, S.; Hirt G.
In: Advanced Engineering Materials, Vol. 17, 2015, 11, pp. 1588–1597
  Determination of thermal boundary conditions for modeling the hot roll bonding process Melzner, A.; Hirt, G.
In: Key Engineering Materials, Vols. 651–653, 2015, pp. 1357–1362
2014   
  Joining of the alloys AA1050 and AA5754 – experimental characterization and multiscale modeling based on a cohesive zone element technique Kebriaei, R.; Vladimirov, I. N.; Reese, S.
In: Journal of Materials Processing Technology, Volume 214, Issue 10, 2014, pp. 2146-2155
  Finite Element implementation of a bonding model and application to roll bonding of aluminum sheets of largely different yield strength Bambach, M.; Pietryga, M.; Mikloweit, A.; Hirt, G.; Karhausen, K.
In: Materials Science Forum Vols. 783–786, 2014, pp. 644-–650
  A finite element framework for the evolution of bond strength in joining-by-forming processes Bambach, M.; Pietryga, M.; Mikloweit, A.; Hirt, G.
In: Journal of Materials Processing Technology, Volume 214, Issue 10, 2014, pp. 2156–2168
  A cohesive zone model for simulation of the bonding and debonding in metallic composite structures − Experimental validations Kebriaei, R.; Mikloweit, A.; Vladimirov, I. N.; Bambach, M.; Reese, S.; Hirt, G.
In: Key Engineering Materials, Vols. 622–623, 2014, S. 443–452
  Development of a testing procedure to determine the bond strength in joining-by-forming processes Mikloweit, A.; Bambach, M.; Pietryga, M.; Hirt, G.
In: Advanced Materials Research Volumes 966–967, 2014, pp. 481–488
  Roll bonding of two materials using temperature to compensate the material strength difference Melzner, A.; Hirt, G.
In: Advanced Materials Research Volumes 966–967, 2014, pp. 471–480
 
 

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