1. Introduction
Metal foams are advanced structural materials used for numerous
applications (see, for example, [1,2]). Depending on a foam
production method it is possible to obtain materials with pores
having different structures [2,3].
A metal can be foamed by means of adding pore-forming agents
into the metal melt at a certain temperature because such agents
are disintegrated actively and release gaseous decomposition
products, which cause the melted mass foaming [1–3]. The subsequent
cooling of the melt allows obtaining the metal foams, which
are characterized by a relatively high uniformity of spatial structural
porosity, if the process parameters are chosen correctly [2].
In order to implement the said method effectively, it is necessary
to match a metal melting temperature and temperature range for
gas release from a pore-forming agent [2,4]. If a foaming agent
releases the gas at the temperature, which is significantly lower
than the metal melting temperature, the metal will start to expand
in its solid state, and therefore cracked pores will form leading to a
non-uniform porous structure. If the foaming agent decomposition
temperature is much higher than the metal melting point, the
metal melt density will be too low for providing the stable foam
formation [2,4].