The technique of using two pure metals, niobium and titanium, to form an electrode in proper form, and to melt and form an ingot under vacuum.Niobium and titanium are active, refractory rare metals that form solid - soluble gold with each othThe alloy as part of the first Ⅱ superconductors, high on the critical field (Hc2). Nb-ti solid dissolved gold can precipitate nb-ti solid dissolved gold under low temperature aging treatment, which makes it have high critical current density.
The cast niobium - titanium alloy has uniform composition and low impurity content. Therefore, not all niob-titanium binary alloy components can be used to manufacture niob-titanium superconducting materials, while the niob-titanium binary alloy components with high Tc and Hc2 should be comprehensively selected to provide superconducting materials.
In fact, the industrial application of niobium titanium superconducting alloy, titanium content is generally 44% ~ 53%.Therefore, niobium titanium superconducting alloy brand nb-44ti, nb-46. 5Ti, nb-48ti, nb-50ti and nb-53ti, etc. In terms of the application of these different components of niob-ti superconducting materials, those with low titanium content are suitable for making superconducting magnets with high field, while those with high titanium content are suitable for making superconducting magnets with low field.
The uniformity and plasticity of ingot casting niobium and titanium belong to different groups of metals.In the process of niobium titanium alloy melting, niobium nonfrit is easy to appear, which affects the uniformity and plasticity of the alloy components. In addition, niobium and titanium have high activity and strong chemical affinity to interstitial elements (nitrogen, oxygen, carbon, hydrogen, etc.).The high uniformity and excellent plasticity of niob-ti superconducting alloy components are important factors for obtaining high critical current density.The critical current density of niob-ti superconducting materials is greatly affected by the dispersion distribution of the precipitated nill binding phase and the final large drawing strain after multiple cold processing and heat treatment.Therefore, in order to prepare niob-ti alloy with high uniformity and low impurity content, ingot casting is a crucial problem in the melting casting alloy technology.
