Porous aluminum is aluminum containing numerous pores, offering lightweight properties and excellent shock absorption. One method for producing porous aluminum is the precursor method. The precursor method involves heating a precursor to generate gas from an internal foaming agent, thereby fabricating porous aluminum. This method allows shaping porous aluminum by forming during the high-temperature state immediately after foaming while maintaining the internal pores. This prevents the densification of porous aluminum during forming. In this study, wave-shaped profiles were formed on porous aluminum immediately after foaming using cylindrical and mountain-shaped dies. X-ray transmission was employed for in-situ observation of the pores of the porous aluminum, and velocity analysis was performed using optical flow. Additionally, cross-sectional observation of the pores of the porous aluminum was conducted via X-ray CT, and porosity was calculated using the Archimedes' principle. The results showed that forming immediately after foaming enables waveform shaping while maintaining internal pores. It was indicated that shape of the porous aluminum changed due to the material flow during shaping with the cylindrical die. Furthermore, it was found that the forming of porous aluminum using mountain-shaped die improved forming accuracy by preventing lateral flow through its mountain-shaped configuration.
Ishiuchi et al. (Wed,) studied this question.