The mechanical properties of the MgB2 bulk materials obtained by reactive liquid Mg infiltration

The Reactive Liquid Infiltration technique (RLI) allows to produce very dense MgB2 bulk material, useful as superconductor in many electro-technical devices. The resulting MgB2 product presents a composite structure characterized by large grains, reminiscent of the grain size of the precursor Boron powders, embedded in a matrix of the same material but with smaller grains, of the order of a micron size. This composite structure of the product presents peculiar mechanical properties characterized by high flexural strength and fracture toughness, as far as a ceramic material is concerned, and very high hardness. We have measured the room temperature mechanical properties as a function of the main RLI manufacturing parameters of the materials and we attempted a correlation with the grain size of the precursor B powders and the residual content of impurities in the materials. The obtained values compare favourably with that of the same material produced by other manufacturing techniques and with that of the other HTS bulk materials. © 2008 American Institute of Physics.