Abstract
In order to achieve improvements in superconducting properties of the Ti-Nb superconductor, effects of teruary additions of Hf have been studied on 42 Ti-Nb-Hf alloys with compositions of 25∼65 at. %Nb, 0∼15 at. %Hf and the balance Ti. Critical temperatures are found to depend upon Hf addition and aging temperature. In as-rolled Ti-40at. %Nb-3at. %Hf alloy the critical temperature is raised by about 0.3K over Ti-40at. %Nb alloy. Aging at 800°C can raise critical temperatures of high Hf alloys by 0.6∼1.8K. The upper critical field at 4.2K of as-rolled Ti-40at. %Nb-3at. %Hf reaches 11.7 tesla, a value higher by 0.4 tesla than that of Ti-40at. %Nb alloy. High field critical current densities are also improved by the 3at. %Hf addition. 2 step aging treatment is found effective in enhancing critical current densities of high Hf alloys. No degradation in fabricability is caused by a few at. %Hf additions.
