Gas Based Hot Forming of Micro-Channels for High Strength Aluminum Alloy Sheets

Abstract:

In carbon-free technologies, thin-walled components with microchannels from ultra-thin sheets, such as bipolar plates, cooling plates, and heat exchangers, are widely utilized. Using such components made of high-strength aluminum alloys further reduces the required wall thickness, thereby enhancing their lightweight potential. However, conventional forming methods for ultra-thin sheets, including elastomer-based deep drawing and hydroforming, are limited by process-induced phenomena such as springback, geometrical inaccuracies and reduced formability as well as localized thinning, which can necessitate a higher wall thickness or the use of a lower strength grade alloy. Gas-based hot sheet metal forming of high-strength aluminum alloys is introduced to improve formability and geometrical accuracy. In the present study, an isothermal, gas-based hot sheet metal forming process is developed for forming microchannels from AlMg3 alloy sheets with a thickness of 0.4 mm. A 100 mm × 100 mm blank is heated to 530 °C and formed under nitrogen gas pressure into a heated die featuring various channel geometries. The effects of blank-holder force, maximum gas pressure, wall angle, channel radius, and maximum channel depth on thinning and form filling are investigated. Additionally, the grain size of the final component is analyzed. A full form filling can be reached under a forming pressure of 200 bar. The thinning is dependent on the micro channel geometry and reaches a maximum of 29 % for a channel depth of 1 mm. The grain size increases during the forming process, dependent on the introduced strain into the material. The proposed method enables forming of components without fracture and with high geometrical accuracy.

• Periodical: Solid State Phenomena (Volume 389)
• Pages: 143-150
• DOI: https://doi.org/10.4028/p-Fi1xWZ
• Online since: April 2026
• Authors: Karl J. Tilly*, Emad Scharifi, Junhe Lian
• Keywords: Hot Metal Gas Forming, Micro-Channels, Ultra-Thin Sheets

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