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为解决Bi-2212线材冷加工过程中的断芯问题,采用中间银丝增强的19×18+1芯的导体结构代替常规的85×7芯的结构,并研究关键热处理参数熔化温度对线材微观结构及载流性能的影响,同时对微观结构的形成机制进行了解释。研究发现,采用中间银丝加强的19×18+1芯结构,可有效防止线材的断芯,显著改善了线材的加工均匀性,线材的载流性能增加了40%。熔化温度对线材载流性能影响较大,温度过高或过低都会导致线材中出现大量尺寸与芯丝尺寸相当的(Sr,Ca)xCuyOδ(AEC相),严重阻碍电流的流通。合适的熔化温度烧结的线材中AEC相较少且尺寸较小,另外还存在较多芯丝间的桥连,增加了电流的输运通道,改善了线材的载流性能。
In order to solve the problem of core breakage during cold working of Bi-2212 wire, the structure of 19 × 18 + 1 core reinforced by intermediate silver wire was used instead of the conventional 85 × 7 core structure and the effect of key heat treatment parameters on the microstructure of wire And current carrying capacity, meanwhile explained the formation mechanism of microstructure. The study found that the 19 × 18 + 1 core structure reinforced by silver intermediate filaments can effectively prevent the breaking of the wire rod and significantly improve the processing uniformity of the wire rod. The current carrying capacity of the wire rod is increased by 40%. The melting temperature has a great influence on the wire current carrying capacity. If the temperature is too high or too low, a large amount of (Sr, Ca) xCuyOδ (AEC phase) with the same size as the core wire will appear in the wire, which seriously hinders the current circulation. The AEC phase is smaller and smaller in the sintered wire with suitable melting temperature. In addition, there are more bridging between the core wires, which increases the current transport channel and improves the wire current carrying performance.