Vickers microhardness measurements were carried out on MgB2 composite wires deformed in Fe sheaths. Because the local hardness of these composites could be simply measured, these values could be used as an indication of the density of the ceramic core. An array of microhardness measurements was performed on single- and multi-core MgB2 wires subjected to variable deformation and heat treatment processes. The results showed how the fabrication process could affect the core density, and so the critical current density, as well as the properties of the metal sheath before and after sintering heat treatments.

Microhardness as a Tool for the Filament Density and Metal Sheath Analysis in MgB2/Fe/(Cu) Wires. I.Husek, P.Kovác, C.R.M.Grovenor, L.Goodsir: Superconductor Science and Technology, 2004, 17, 971-6