Interpenetrating Composites: A Nomenclature Dilemma.

Interpenetrating phase composites are a novel class of heterogeneous structures that have recently gained attention. In these types of composites, one of the phases is topologically continuous and can maintain its structural integrity even if the other phase is removed. These composites are generally fabricated by casting, where the reinforcement penetrates into the precursor matrix as a continuous phase. However, the following dilemma arises: if the same two phases are combined by other powder metallurgical routes (due to differences in the fabrication and interfacial conditions), can they still be called interpenetrating phase composites? The reinforcement is added to the precursor matrix, as in any of the conventional composite processing methods. Most importantly, the reinforcement does not interpenetrate the matrix phase. The present Review discusses the various fabrication routes employed for the fabrication of these interpenetrating phase composites and attempts to identify the correct nomenclature for these composites fabricated via the powder metallurgical approach.