X-ray radiography inspection of pores of thin aluminum foam during press forming immediately after foaming

Abstract

Forming aluminum foam to the desired shape while retaining its pore structures is essential for manufacturing aluminum foam products. Recently, a press forming process for aluminum foam that is performed after precursor foaming but before solidification has been proposed. In this study, to track individual pores throughout press forming immediately after foaming, X-ray radiography inspection was applied. A thin precursor was used, and foaming was constrained to the X-ray transmission direction. It was shown that, although some pores coalesced with other pores, the pores did not collapse during press forming. In addition, the porosity of aluminum foam evaluated from X-ray transmission images was constant during press forming. Some pores retained their shape during press forming but their position was changed by the material flow generated by press forming. These results show that by press forming before the solidification of aluminum foam, aluminum foam can be shaped without the collapse of pores.