Modelling of the Mechanical Interlocking by Surface Structures during Cold Rolling of Multi-Material Components

Journal of Physics Conference Series, vol. 3104, pp. 012098

Abstract

Abstract In sandwich structures, a corrugated core layer is often joined to cover layers along a seam. The lightweight construction potential and high rigidity make such components attractive for a wide range of applications, e.g. for battery housings of electric vehicles. One multi-material approach uses a layer of steel with higher strength for impact protection and an aluminium sheet with low weight and high thermal conductivity for cooling. However, joining of dissimilar materials presents challenges. Metallurgical bonding methods, such as fusion welding, can result in brittle intermetallic phases at the interface. Fasteners like rivets add extra weight and create localized joints only, while adhesives typically exhibit lower strength and adverse aging effects. To overcome these drawbacks, this study proposes a process in which two materials are mechanically joined along a longitudinal seam by cold rolling. First, surface structures with undercuts are rolled into a stronger base material. Secondly, softer material is rolled into the structures. A 2D forming simulation is created to illustrate the rolling of Al99.5 sheets into surface structures on DC04 sheets and experimentally validated. To explore the limits with regard to the strength ratio of the materials two aluminium grades with higher yield strength (AlMg3, AlMg4.5) are selected for simulation and validation experiments. The results indicate that a yield strength ratio exceeding 1.4 is essential for successful joining by cold rolling. At lower ratios, the aluminium flow into the steel’s surface structure is insufficient.

Authors 4

1. Aron Ringel Aachen Institute of Metal Forming

   RWTH Aachen University

   Affiliation as printed

   Institute of Metal Forming, RWTH Aachen University, Aachen, Germany

2. Oliver Edwin Aachen Institute of Metal Forming

   RWTH Aachen University

   Affiliation as printed

   Institute of Metal Forming, RWTH Aachen University, Aachen, Germany

3. Emad Scharifi Aachen Institute of Metal Forming

   RWTH Aachen University

   Affiliation as printed

   Institute of Metal Forming, RWTH Aachen University, Aachen, Germany

4. David Benjamin Bailly Aachen Institute of Metal Forming

   RWTH Aachen University

   Affiliation as printed

   Institute of Metal Forming, RWTH Aachen University, Aachen, Germany