Investigation of effect of annealing temperature on mechanical properties of MgB2

The effect of annealing temperature on the microstructure, magnetic and mechanical properties of MgB2 superconducting samples has been studied. The study consists of XRD, SEM, ac susceptibility, Vickers microhardness and density measurements. These measurements indicated that the grain sizes, lattice parameters, density, and critical transition temperature increase and the grain connectivity are improved with increasing the annealing temperature up to 850 degrees C. It was also found that the Vickers microhardness of the samples was dependent on the annealing temperature and applied load. In addition, we calculate the load dependent mechanical properties of the samples using different model. We have discussed the possible reasons for the observed improvements in microstructure, superconducting and mechanical properties due to annealing temperature. (C) 2008 Elsevier B.V. All rights reserved.