New Insights into Fabrication of Al-Based Foam with Homogeneous Small Pore-Structure Using MgCO₃/Zn Composite Powder as a Foaming Agent

Abstract

Due to its excellent mechanical properties and ultra-lightweight, Al-based foam with homogeneous small pore-structures has wide applicational prospects in many industrial fields. However, during the foaming process of molten Al, it is difficult to manipulate the pore structures of the Al-based foam by means of the ALPORAS© production route due to the violent gas-releasing performance of TiH2 as a traditional foaming agent. Herein, we developed the melt-foaming route, that is, using MgCO3/Zn composite powder as a foaming agent instead of TiH2, the Al-based foam with homogeneous small pore-structures (average diameter was about 1 mm) was prepared successfully. Meanwhile, the decomposition model of the MgCO3/Zn composite powder was proposed and further verified experimentally. The decomposition kinetics of the MgCO3/Zn composite powder was also analyzed. Our findings not only shed light on the practical manufacturing of Al-based foam with homogeneous small pore-structures, but provide an insightful improvement for melt-foaming approaches.

Keywords

• Al-based foams
• pore-structure
• MgCO₃/Zn composite powder
• melt foaming method