SBIR Phase II: Development of Artificial Pinning Center Niobium Titanium Superconductors with Optimal Overall Compositions

这个小型企业创新研究二期项目将研究使用一种新的人工钉住中心方法改变铌钛（NbTi）超导体组成的可能性。第二阶段的技术目标是开发一种通过人工钉钉中心（APC）工艺生产商业规模坯料的工艺，并针对特定应用优化成分。将选择两种不同的组合物，一种用于高强度野外使用，另一种用于低至中等强度野外使用。此外，生产单丝材料的工艺也将从研发规模扩大到商业规模的坯料。所有传统生产的NbTi超导体都使用单一成分的熔化合金，Nb47wt%Ti。经济和技术上的限制阻碍了其他合金成分的使用。Supercon APC工艺使用纯Nb和Ti片材作为起始材料，因此可以通过改变片材的厚度来改变整体的NbTi成分。通过改变组合，应该能够为特定的应用程序优化组合。例如，用于高磁场（7T）的导体必须在这些磁场中具有最高的临界电流密度。因此，最优的组合物将是优化上部临界场的组合物。对于用于低场应用的导体，如MRI，峰值场不超过5T。此外，这些应用对以$/Kamp * m为单位测量的导体成本非常敏感。在这种情况下，高钛含量的合金将具有吸引力。结果表明，高Ti含量的复合材料可以获得比传统熔融合金更高的低场Jc。使用较高的Ti含量降低了原材料成本，因为Ti取代了昂贵2-4倍的Nb。该SBIR计划将为具有优异Jc性能的NbTi超导体的制造提供一种高度经济的工艺。传统的NbTi合金衍生超导体是Supercon APC材料的主要竞争产品。优化长丝成分、不需要NbTi合金和传统的沉淀热处理、良好的延展性将为APC材料与传统材料竞争提供必要的成本优势。可以从这些改进中受益的应用包括MRI、实验室螺线管、磁矿分离、磁流体动力推进、磁悬浮、聚变和高能物理磁体以及核磁共振。

9531315 Wong This Small Business Innovation Research Phase II project will investigate the possibility of varying the composition of Niobium Titanium (NbTi) superconductors by using a novel artificial pinning center approach. The technical objective of the Phase II is to develop a process for producing commercial scale billets via the Artificial Pinning Center (APC) process with compositions optimized for a particular applications. Two different compositions will be chosen, one for high field use, the other for low to intermediate field use. In addition the process to produce monofilamentary material will also be scale from R&D to commercial sized billets. All conventionally produced NbTi superconductors use a melted alloy of single composition, Nb47wt%Ti. Economic and technical limitations have prevented the use of other alloy compositions. The Supercon APC process uses pure Nb and Ti sheets as the starting material, thus overall NbTi composition can be varied simply by changing the thickness of the sheets. By varying composition, one should be able to optimized composition for particular applications. For example, conductor that is used at high fields (7T) must have the highest critical current densities at these fields. Thus the composition that is most optimal would be one that optimizes the upper critical field. For conductor that is used in low field applications, such as MRI, peak fields do not exceed 5T. In addition, these applications are very sensitive to conductor cost as measured by $/Kamp * M. In this case a higher Ti content alloy would be attractive. It has been shown that higher Ti content composites can achieve low field Jc's higher than the conventional melted alloy. The use of higher Ti content reduces the raw material costs, as the Ti replace Nb which is 2-4 times as expensive. This SBIR program will results in a highly economical process for the fabrication on NbTi superconductors with excellent Jc performance. Conventional NbTi alloy derived superconduc tors are the principle competing product for this Supercon APC material. Optimizing filament composition, elimination of the need for NbTi alloy and conventional precipitation heat treatments, and good ductility should provide the necessary cost advantage for APC material to compete successfully with conventional material. Among the applications that can benefit from these improvements are MRI, laboratory solenoids, magnetic ore separation, magneto-hydrodynamic propulsion, magnetic levitation, fusion and high energy physics magnets, and nuclear magnetic resonance.