Effects of Porosity and Pore Structure on Compression Properties of Blowing-Agent-Free Aluminum Foams Fabricated from Aluminum Alloy Die Castings

Aluminum foam was fabricated without the use of a blowing agent by a friction stir processing route using ADC12 aluminum alloy die castings, which contain a large number of gas pores. In this study, ADC12 foams with a porosity of 50-77% were successfully fabricated, and the pore structures and compression properties of the obtained ADC12 foams were investigated. The ADC12 foams had smaller pores than commercially available aluminum foam. Moreover, the pore size of the ADC12 foams was almost the same regardless of the porosity. According to the results of compression tests, the plateau stress and energy absorption tend to decrease with increasing porosity. Commercially available aluminum foam exhibited higher energy absorption at a low compression stress, whereas the ADC12 foams exhibited higher energy absorption at a high compression stress. Also, the ADC12 foams with higher porosity exhibited higher energy absorption per unit mass, regardless of the compression stress. In contrast, the energy absorption per unit volume was greatest for the low-porosity ADC12 foam at a low compression stress but greatest for the high-porosity foam at a high compression stress. [doi:10.2320/matertrans.M2012125]