Structure of MgB2 Ceramics Synthesized with Excess of Magnesium after Cold Deformation and Annealing

—In a bulk MgB2 compound synthesized with an excess of magnesium, a structure that could provide high critical currents has been obtained as a result of deformation by upsetting and subsequent annealing at 650°C for 7 h. The investigation of this structure using X-ray diffraction and scanning and transmission electron microscopy methods has shown that a dense nanosized matrix MgB2 phase with good intergrain bonding is formed in the obtained material. In the matrix phase, there are uniformly distributed dispersed inclusions of MgO, which could serve as pinning centers.