Application of metal hydrides as pore-forming agents for obtaining metal foams

• Pre-oxidized titanium hydride powder is a suitable blowing agent for aluminum foams.
• The optimal mode of powder oxidation by air oxygen is warming up at ∼440 °С for 1 h.
• The external pressure is the influential factor affecting the foaming process.

One of the well-known ways of metal foam production consists of adding powder which releases gaseous decomposition product at high temperatures into a melted metal. When producing aluminum foams, titanium hydride powder is most frequently used, while its main disadvantage is its insufficient thermal stability. This results in a premature gas loss in the process of the powder introduction into a melted metal matrix. The paper discloses approaches to suppression of the undesirable premature titanium hydride decomposition by means of its preliminary thermal treatment, as well as the external pressure elevation over that of the system being processed during the foam formation. A method of using the thermally treated powder is proposed, in order to obtain aluminum foam samples having a required geometry and sufficiently uniform porous structure.