Evolution of core connectivity in MgB2 wires and tapes during PIT processing

Investigation of effect of annealing temperature on mechanical properties of MgB2

“…3. As can be seen from [5,6,12,24]. It was observed that the microhardness values increased with increasing annealing temperature from 650 to 850 • C and it decreased at 950 • C. At 950 • C, the bonding strength decreases and consequently microhardnes value is degraded.…”

An analysis of load-depth data in depth-sensing microindentation experiments for intermetallic MgB2

“…Besides, the calculated values of the present work are comparable with the results of other works in the literature. In the literature, the microhardness and reduced modulus of intermetallic MgB 2 specimens have values falling within the range of H = 0.5-12.79 GPa, E = 19-80.5 GPa [9][10][11][12]. It is obviously seen from the literature that the reported microhardness and reduced modulus values show a significant variation.…”

“…On the other hand, the mechanical properties such as hardness, elastic modulus, fracture toughness, ductility, etc., are as important as the critical temperature, the critical current density, and the critical magnetic field for industrial applications of superconductor materials. Accordingly, the MgB 2 superconductors have higher mechanical strength than the other HTc ceramic superconductor materials [8][9][10][11][12]. Therefore, investigation of the mechanical properties of intermetallic MgB 2 superconductors for potential application in industry is important.…”

“…In the literature, a few studies deal with the mechanical behavior of MgB 2 superconductors via conventional experimental procedure [9][10][11][12]. According to our best knowledge, depth sensing indentation analysis has not been performed on intermetallic MgB 2 materials, although the depth sensing experiment is more precise than the conventional experimental procedure.…”

Current densities of MgB2 wires by combined ex situ/in situ process

“…The core density of Ex route is influenced by the applied sheath material, fill factor, and deformation reaching maximally 90% of theoretical one ͑2.6 g / cm −3 ͒. 7 High core porosity is typical for In route due to the volume shrinking taking place during the transformation of the Mg+ B mixture into the MgB 2 compound. The volume ratio of ͑V Mg +2V B ͒ / V MgB2 is 1.3, which corresponds to a 30% space reduction during the In process.…”