Development of a forming process for aluminum sheets at cryogenic temperatures

• Applicant: Professor Dr.-Ing. Alexander Brosius
• Subject Area: Primary Shaping and Reshaping Technology, Additive Manufacturing
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 542202029

Lightweight materials such as aluminium alloys play an important role in weight reduction. However, their limited formability at room temperature poses a major challenge and restricts their use. Significant improvements in formability can be achieved, for example, through recovery annealing or hot forming with several process steps. However, this improvement in formability comes at the expense of various positive properties such as strength, component quality or costs. To avoid this, aluminium sheets can be formed at cryogenic temperatures, whereby the limit for adjusting the positive properties is to be the subject of the research applied for here. The main research question to be addressed in the proposed research project is the combination of cryogenic sheet metal forming with the macro-structuring of the die and blank holder during deep drawing. In contrast to conventional deep-drawing tools, the contact surface between the tool and the sheet metal in the area of the blank holder is reduced by a special, wave-like geometry of the forming tools. The research approach here is therefore based on minimising the contact surface between the sheet metal and the tool in order to suppress the heat flow and thus the heating of the sheet metal. The aim of this project is therefore to investigate how the use of macro-structured tools makes it possible to maintain the sheet metal temperature in the cryogenic range during forming without the need for additional cooling of the tools or the environment. In order to achieve this goal, a method for the local geometric design of the macro-structuring must be developed so that the heat flow between the tool and the workpiece is reduced to a minimum and wrinkling during the deep drawing process is avoided. In addition, the local limit temperature of the sheet metal must be determined, above which the advantages of the cryogenic material properties of aluminium alloys come into play. The limit temperature is therefore the relevant process variable, and the technological control of the temperature balance during the transient process sequence is the primary research task associated with the identification of a suitable process control strategy.

• DFG Programme: Research Grants