| Summary: | The efficiency of new artificial pinning centres have been investigated in NbTi using the oxide dispersion strengthening (ODS) concept more typically applied to steels and Ni-superalloys. NbTi alloys containing a dispersion of nanoscale Y2Ti2O7 particles have been successfully manufactured through a powder metallurgy route by mechanical alloying Nb, Ti and Y2O3 nanopowders using high energy ball milling and subsequent consolidation and annealing. The microstructure and superconducting properties of the NbTi-Y2O3 have been characterised after each processing step. After 40 h of ball milling, the Y2O3 particles are dissolved into the nanostructured NbTi matrix formed by mechanical alloying of Nb and Ti. On annealing at temperatures above 800 °C the dissolved Y and O react with Ti from the matrix, and fine Y2Ti2O7 particles (<5 nm) are precipitated. These NbTi-Y2Ti2O7 composites showed excellent superconducting performance, with JC of 5.2 kAmm−2 at 4.2 K, 5 T, considerably higher than Y2O3-free bulks manufactured using the same process and NbTi wires manufactured using the conventional thermomechanical process. The results suggest that ODS powder processing is a promising new route to manufacture NbTi alloys containing artificial pinning centres that give superior superconducting properties.
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