Thermographic investigation of strain rate effects in Al foams and Ni/Al hybrid foams

Abstract

Open-cell metal foams are biomimetic open-porous materials mimicking the construction elements of bones. Based on their special porous microstructure, they are used as lightweight construction elements and for crash energy absorbers. Ni/Al hybrid foams are aluminium (Al) foams electrochemically coated with nanocrystalline nickel (Ni) leading to enhanced strength and energy absorption capacity. A robust understanding and knowledge of the deformation behaviour under different strain rates are essential to design crash absorbers made of foams. The present contribution is focused on the investigation of strain rate effects and is furthermore a pioneering work dealing with a full thermomechanical characterisation of the deformation behaviour in Al foams and Ni/Al hybrid foams by a combination of digital image correlation for measuring local strain fields and infrared thermography for measuring local temperature fields during the deformation process.