EFFECT OF THE POWDER STRAIN STATE ON THE MECHANICAL PROPERTIES OF MGB2 TAPES

M. T. MALACHEVSKY; A SERQUIS; G. SERRANO; J. P. MORALES ARIAS; G. GIUNCHI

Washington

Conferencia; Applied Superconductivity Conference 2010; 2010

ASC

Starting from commercial MgB2 powder of 325 mesh, we further reduced the agglomerates by attrition milling in nitrogen atmosphere to minimize oxidation. Using different milling media (tungsten carbide, yttria stabilized zirconium oxide and stainless steel balls), we studied the evolution of the strain state and crystallinity of the powders by x-ray diffraction. We prepared single filament tapes with the obtained powders and analyzed the resulting microstructures when using a soft (silver) and a hard (stainless steel) metal sheath, heat treated for 2.5 hours at 850 C in argon. We characterized the superconducting properties by determining the magnetic Jc in a SQUID. The mechanical properties of the tapes were analyzed using a 4-point bending micro-tests. Some monel-sheathed and titanium-sheathed tapes were measured for comparative purposes. We discuss the influence of the metal sheath on the stress-strain characteristics of the tapes.