New nanoscale artificial pinning centres for NbTi superconductors
The Oxide-Dispersion-Strengthening (ODS) concept, more typically applied to steels and Ni-superalloys, has been used for the first time for NbTi superconductors to generate nanoscale artificial pinning centres and improve current densities.
The powder processing of Nb, Ti and Y2O3 followed by a subsequent consolidation and annealing process successfully leads to create Y2Ti2O7 nanoparticles (<5 nm) dispersed over a nanostructure NbTi matrix.
Y2Ti2O7 nanoparticles act as pinning centres with new pinning mechanisms different from those of α-Ti known as effective pinning centres in NbTi alloys for many years.
A new processing route along with ODS concept generates a particular microstructure in NbTi alloys, leading to a high value of current densities (>5.4 KAmm-2 at 4.2 K and 5 T), much larger than the current densitities reported for NbTi fabricated through conventional melt-processing methods.
The full paper can be read in the journal Materials & Design.