Controllable Design of Structural and Mechanical Behaviors of Al–Si Foams by Powder Metallurgy Foaming

Abstract

The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adem.202200125.

Review: Closed-Cell Metallic Foams Produced via Powder Metallurgy

“…These alloying elements generally serve to lower the solidus temperature, increase the expansion percentage, and reduce the pore size. When excessive alloying particles are added they can form agglomerations which can accelerate the pore coalescence [31]. The melting of the foamable precursor is correlated with expansion, and by lowering the solidus temperature, this process begins closer to the blowing agent decomposition temperature.…”

“…Not only can the heating rate affect foaming but so does the cooling rate at the end of the foaming process. Following foaming, foams can be quenched with air or water to freeze the pore structure or allowed to cool in ambient air [31,73,125]. Freezing the pore structure in place through quenching enables the analysis of pore growth/evolution and can reduce coalescence [37].…”

“…The production of closed-cell metallic foams using the PM route has been referred to in the literature by different names. For example, the PM route/powder foaming process [26,27], powder metallurgy process [28], powder compact process [29], powder compact route [30], powder compact melting technique [25], powder metallurgy foaming [31], the Fraunhofer process [32], and the powder compact melting process (PCMP) [17]. We, however, propose the name Powder Compact Melt Foaming Process (PCMFP), as this name more effectively captures the physics governing this process, whereas other names could also be applied to other processes or foams, e.g., for open-cell foams (the 'powder metallurgy route' was used to describe the processing of open-cell Mg foam [33]), or foaming using a blowing agent during solid state sintering [34,35] (not melting).…”