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

Abstract

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 5077% 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.

Compression Properties of Al/Al–Si–Cu Alloy Functionally Graded Aluminum Foam Fabricated by Friction Stir Processing Route

“…In Fig. 4(g) and Table 2, the results for uniform ADC12 foam with a porosity of 76.5% presented in a previous study, 20) which experiment was conducted by the lower aspect ratio of the specimen than the specimen used in this study, are also shown. This foam did not exhibit a decrease in stress during compression tests.…”

“…In the uniform ADC12 foam, parts of the cell wall collapsed as a result of local brittle fracture during compression because ADC12 Al alloy is composed of brittle eutectic AlSi alloy, and the true cross-sectional area decreased. 20) Also, the aspect ratio of the specimen used in this study was comparatively high. In Fig.…”

“…17,18) These gases can be used for foaming to fabricate Al foam without using a blowing agent. 19,20) First, as shown in Fig. 1(a), Al plates were stacked with powders distributed between them.…”

Plateau stress estimation of impact compression test on aluminum foam using X-ray computed tomography observation

“…The ADC12 plate potentially contained some gases. These gases were used to fabricate Al foam without using a blowing agent (Hangai et al, 2012b, Utsunomiya et al, 2011. The amount of Al 2 O 3 powder was 5 mass% relative to the mass of the plate with the above stirred volume for all the plates.…”

Estimation of Plateau Stress of Porous Aluminum Based on Mean Stress on Maximum-Porosity Cross Section

“…As shown in Figs. 1(b)1(d), the probe of a rotating tool was inserted into plates A and B, and multipass FSP of 5 lines © 4 passes was applied to obtain a larger precursor and to mix the gases and powders thoroughly 10,11) using an FSW machine (SHH204-720, Hitachi Setsubi Engineering Co., Ltd.). Moreover, as shown in Fig.…”