Artificial Pinning Center Niobium Titatium Superconductors with Optimal Overall Compositions

这个小型企业创新研究第一阶段项目开发具有人工钉扎中心的NbTi超导体，在性能和成本方面具有最佳组合。 Supercon开发了一种专利和成熟的工艺，用于使用人工钉扎中心方法（APC）制造NbTi超导体，该方法通过纯金属的部分扩散组装Nb和Ti金属的交替层以形成超导细丝。它允许一个有独立的控制灯丝的有效成分，以及非超导相（钉扎中心）的厚度和间距。常规的NbTi复合材料制造使用- Nb-47 wt. % Ti，适用于大多数应用。原则上，Supercon APC方法可以制造具有几乎任何有效总体组成的长丝的复合材料。邻近效应被认为将具有工业上有用的Tc和Hc 2的实际NbTi合金组合物限制在40至65 wt. % Ti。文献中报道的大多数APC导体具有在该范围的富Nb侧上的总体组成。结果，Hc 2降低，并且与常规合金相比，原材料的成本增加。这项拟议的工作建立在Supercon现有的APC制造经验的基础上，以优化具有不同长丝成分的新复合材料，适用于特定的应用磁场范围，同时最大限度地减少Nb含量，从而降低每种情况下的成本。第一阶段的努力的技术目标是了解如何独立地改变组合物（相对Nb和Ti层厚度）和第二相体积分数（热处理条件）的影响APC NbTi超导复合材料的微观结构，机械和电气性能（Jc和HC 2）。

This Small Business Innovation Research Phase I project develops NbTi superconductors with artificial pinning centers with an optimal composition in terms of performance and cost. Supercon has developed a patented and proven process for the manufacture of NbTi superconductors using an artificial pinning center approach (APC), which assembles alternate layers of Nb and Ti metals to form a superconducting filament through partial diffusion of the pure metals. It allows one to have independent control of the filament effective composition as well as both the non-superconducting phase (pinning center) thickness and spacing. Conventional NbTi composite manufacturing uses- Nb-47 wt. % Ti for most applications. In principle, the Supercon APC approach can fabricate composites with filaments of almost any effective overall composition. The proximity effect is thought to limit practical NbTi alloy compositions with industrially useful Tc and Hc2 to within the range of 40 to 65 wt. % Ti. Most APC conductors reported in the literature have an overall composition on the Nb rich side of this range. As a result, the Hc2 is reduced, and the cost of the raw materials is increased over a conventional alloy. This proposed work builds upon existing APC manufacture experience at Supercon to optimize new composites with different filament compositions suitable for specific applied magnetic filed ranges, while minimizing the Nb content and therefore cost in each case. The technical objective of the Phase I effort is to understand how independently varying both the composition (relative Nb and Ti layer thickness) and the second phase volume fraction (thermal processing conditions) effect the microstructural, mechanical, and electrical properties (Jc and Hc2) of APC NbTi superconducting composites.