Effects of Amounts of Blowing Agent and Contained Gases on Porosity and Pore Structure of Porous Aluminum Fabricated from Aluminum Alloy Die Casting by Friction Stir Processing Route

Abstract

Porous aluminum is expected to be applied as a multifunctional material in various industrial fields because of its light weight and high energy absorption. When aluminum alloy die castings are used as a starting material in the fabrication of porous aluminum, it can be expected that, by effectively using the gases intrinsically contained in the die casting to generate pores, porous aluminum can be fabricated by adding a small amount of blowing agent. In this study, while systematically varying the amount of blowing agent from 0 to 1.4 mass% that is added to ADC12 aluminum alloy die castings containing three different amounts of gases, porous aluminum is fabricated by the FSP (friction stir processing) route precursor method. Titanium(II) hydride powder is used as the blowing agent. The variations of porosity and pore structure with the amount of added blowing agent are investigated for each amount of gases contained in the die castings. On the basis of the results, it is shown that, by using a blowing agent of approximately 0.6 mass%, ADC12 porous aluminum with high porosity can be fabricated regardless of the amount of gases contained in the die casting.

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

“…In addition, it was shown that the pores of the Al foam obtained using die castings without the use of a blowing agent are smaller and have higher sphericity than those of Al foam fabricated using a blowing agent. 17,18) Therefore, it is expected that the Al foam fabricated from aluminum alloy die castings without the use of a blowing agent will exhibit different mechanical properties from those of Al foam fabricated using a blowing agent. 14) Although other researchers have also demonstrated blowing-agent-free processes for fabricating Al foam by the P/M route, 1921) few studies have been conducted on these processes.…”

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

“…During the heating process, the low-melting-point ADC12 first foamed, and the bonding region also foamed before the A1050 because it contained both gases and the blowing agent. The high expansion efficiency of the blowing agent, as shown in the reference, 24) and the earlier occurrence of foaming resulted in the coalescence of pores. Table 1 shows the porosity and pore diameter of the A1050 and ADC12 layers of the FG foam, along with those of uniform A1050 and ADC12 foams.…”

Relationship between Porosity and Interface Fracture on Aluminum Foam Sandwich with Dense Steel Face Sheets Fabricated by Friction Stir Processing Route

“…This tendency is similar to the results in a previous study. 17) However, when V b was 0.05 mass%, the values of p were scattered in a wide range of approximately 5567%. This is mainly because it was difficult to distribute the powder uniformly (cf.…”