Multipass equal channel angular extrusion of MgB2 powder in tubes

In the current study multipass equal channel angular extrusion (ECAE) is adopted for the first time to study the applicability of the process to compact magnesium boride (MgB2) powder in tubes (PITs). The influence of number of ECAE passes on MgB2 PITs was also analyzed in terms of microstructure, density and mechanical properties. MgB2 PITs with iron tube were processed up to six ECAE passes. X-ray analysis of the compacts showed no other phases, other than MgO, in MgB2 compacts even after large mechanical working and annealing. Simple shear stresses predominant in ECAE constantly rendered compaction of the hard brittle MgB2 powders.