Nb3Al超导材料的高场特性及调控机理

Compared with the commercialized high-field superconductor Nb3Sn, Nb3Al posseses higher superconducting critical temoerature, higher upper critical field, better current-carrying capacities, and higher stress tolerance of the current-carrying capacities, thus having high potential in high-field applications including the future magnetic confinement nuclear fusion reactor. However, on one hand Nb3Al is hard to be formed due to its complicated phase-formation-diagram, and on the other hand, it is difficult to control its microstructure and defect structure. Moreover, the flux pinning mechanism for Nb3Al is also not yet clear to date. All this makes it hard to control and optimize the high-field superconducting properties for Nb3Al. In order to fabricate high quality Nb3Al superconducting wires, and further to improve their stress-tolerant properties in high-field, this project will focus on the research of the mechanism of the Nb3Al phase-formation, the microstructure and defect structure control, and the mechanism of the flux-pinning and element doping effect as well. As a result of the researches mentioned above, it is expected that Nb3Al superconducting wires with better performance may be fabricated, which will provide strong support to the high-filed applications in future.

商业化的高场超导材料Nb3Sn相比，Nb3Al超导材料具有更高的临界磁场、临界电流密度和应变容许特性，因而在未来磁约束核聚变堆和其它高磁场磁体中具有广阔的应用前景。然而，Nb3Al的成相过程复杂、微观结构和缺陷结构调控难度大、磁通钉扎机理尚不明确，从而导致其高场性能、力学性能难以调控和提升，这已经成为制备高品质的Nb3Al材料以及优化其超导性能的障碍。为了获得高性能的Nb3Al材料、主动调控和优化其高场性能和应变容许特性，本项目将系统研究Nb3Al成相规律与微观结构、缺陷态控制机理、研究其微观结构与超导和力学性能的关联，以期阐明Nb3Al超导材料的高场特性和磁通钉扎机理，为优化和调控Nb3Al的超导应用性能寻求科学依据。在此基础上，将探索高性能的Nb3Al超导衍生材料，为人类在未来高场超导磁体的材料制备和技术应用方面提供更好的途径。

与商业化的高场超导材料Nb3Sn相比，Nb3Al超导材料具有更高的临界磁场、临界电流密度和应变容许特性，因而在未来磁约束核聚变堆和其它高磁场磁体中具有广阔的应用前景。然而，Nb3Al的成相过程复杂、微观结构和缺陷结构调控难度大、磁通钉扎机理尚不明确，从而导致其高场性能、力学性能难以调控和提升，这已经成为制备高品质的Nb3Al材料以及优化其超导性能的障碍。为了获得高性能的Nb3Al材料、主动调控和优化其高场性能和应变容许特性，本项目系统研究了Nb3Al成相规律与微观结构、缺陷态控制机理、研究其微观结构与超导和力学性能的关联，以期阐明Nb3Al超导材料的高场特性和磁通钉扎机理，为优化和调控Nb3Al的超导应用性能寻求科学依据。.经过四年的系统研究，我们获得了对Nb3Al体系的深刻认识。开发了机械合金化制备Nb-Al饱和固溶体技术、开发热压法制备高性能 Nb3Al 超导材料的技术、掌握了快速升温快速淬火（RHQ）技术以及卷绕法与快热急冷淬火技术结合，显著提高Nb3Al长线材的性能、获得高性能Nb3Al线材；开发了用Ge掺杂调控Nb3Al的制备工艺和性能，在高性能Nb3Al超导线材在高场下的超导性能研究中，揭示了层错是Nb3Al钉扎中心的来源；获得 Nb3Al材料在晶体结构、组分与超导临界温度的关联规律；掌握了Nb-Al界面反应扩散的规律、并揭示了不同Nb-Al饱和固溶相形成Nb3Al相的机理。这些成果将为未来高场超导磁体的材料制备和技术开发提供更佳的途径。