【摘要】 采用套管法,结合挤压、拉拔和轧制等塑性加工过程制备了Nb3Al超导线材前驱体长线,并利用自主设计制作的急热急冷(~2000℃,RHQ)装置对线材样品进行RHQ热处理和低温成相退火,获得了高性能的Nb3Al超导线材.结果表明,该线材由管状Nb3Al超导体、Nb基体骨架和孔洞组成;即通过RHQ热处理使Al芯与周围的Nb实现固溶体化,并留下孔洞,随后的低温成相退火使Nb-Al固溶体生成了管状Nb3Al超导体,而在距离Al源较远的位置则留下未反应的Nb基体骨架.通过扫描电子显微镜和磁化率测量显示,该线材中Nb3Al超导体具有精细的晶粒尺寸(50~100 nm)和良好的晶粒连接性;不同样品的起始超导转变温度(Tc)均达到了约17 K,表明该线材中Nb3Al超导体的Nb/Al原子比接近理想的3:1.因此,利用套管法有望制备出满足下一代高场磁体应用的高性能Nb3Al超导线材.更多还原

【Abstract】 In this work, rod-in-tube(RIT) method was utilized to make the Nb3 Al precursor long wires, combing with hot-extrution, drawing and rolling process, and consequently high-performance Nb3 Al superconducting wires had been made, which stood up a rapid heating, quenching(RHQ) and low-temperature annealing process by using the home-made RHQ equipment up to 2000°C. The results suggest the Nb3 Al superconducting wires compose with tubular Nb3 Al superconductors, Nb-matrix and holes. By RHQ heat-treatment, Al cores dissolved into the Nb-matrix, reacted with the near Nb layer, and left the holes. After low-temperature annealing, the Nb-Al solid-solution was changed into tubular Nb3 Al superconductor, and un-reacted Nb, far from the Al source, was the Nb-matrix. The SEM and magnetization susceptibility measurements present these Nb3 Al superconductors are with fine grains of 50–100 nm, and well grains-connectivity. All of the onset superconducting transition temperature Tc reach about 17 K, which imply they have Nb/Al atom ratio of 3:1. Therefore, using the RIT Nb/Al precursor wires and RHQ heat-treatment is promising to develop the next-generation high-performance Nb3 Al superconducting wires for high-field magnet application.更多还原