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本文通过高温金相、电子探针、阳极氧化、金相观察、X 光相分析和测定显微硬度等手段,研究了 NbTi50/Cu 复合超导体中Cu—Ti 扩散形成的金属化合物层的生成规律、性质及其组成;并研究了扩散层对该材料机械性能的影响,从而为选择该材料的最佳挤压(或热轧)温度提供依据。NbTi50/Cu 复合超过材料在加工过程中因 Cu 与 Ti 的相互扩散,在 NbTi 芯与 Cu的界面处形成脆性的金属化合物层,影响加工性能,导致该材料载流能力降低。我们多年来研制 NbTi50/Cu 复合超导材料的实践,认为脆性的 Cu—Ti 化合物层是造成细丝断芯的主要原因之一。本实验的目的是探讨 Cu—Ti 扩散层的生成规律、性质、组成及对该材料机械性能的影响,为选择最佳挤压(热轧)温度提供依据。为此,我们用高温金相法研究了高温及高温压缩情况下扩散层的生成规律,如不同温度下扩散的方式、变化的情况等;用电子探针测定了扩散层的厚度、描绘了扩散层的扫描曲线、测定了各相的成分;用阳极氧化法观察了扩散层;测定了扩散层的显微硬度及各种热处理制度下该材料的机械性能。据实验观察,我们认为780±3℃是 Nb—Ti—Cu 的三元共晶点。关于共晶点问题有待进一步研究。
In this paper, the formation law of Cu-Ti diffusion in the NbTi50 / Cu composite superconductors was studied by means of high-temperature metallography, electron probe, anodic oxidation, metallographic observation, X-ray phase analysis and determination of microhardness. Properties and composition of the material were investigated. The effect of diffusion layer on the mechanical properties of the material was also studied, which provided the basis for selecting the optimal extrusion (or hot rolling) temperature of the material. Due to the mutual diffusion of Cu and Ti during the process of NbTi50 / Cu composite overcrossing, a brittle metal compound layer is formed at the interface between NbTi core and Cu, which affects the processability and leads to the decrease of current carrying capacity. We have developed the practice of NbTi50 / Cu composite superconducting materials for many years and believe that the brittle Cu-Ti compound layer is one of the main reasons for the broken filaments. The purpose of this experiment is to investigate the formation regularity, property, composition of the Cu-Ti diffusion layer and its influence on the mechanical properties of the material, to provide the basis for choosing the best extrusion (hot rolling) temperature. For this reason, we used high-temperature metallographic method to study the formation law of diffusion layer under the condition of high temperature and high temperature compression, such as the way of diffusion under different temperature, the change situation, etc .; The thickness of diffusion layer was measured by electron probe, Scanning curves were taken to determine the composition of each phase. The diffusion layer was observed by anodic oxidation. The microhardness of the diffusion layer and the mechanical properties of the material under various heat treatments were measured. According to experimental observations, we believe that 780 ± 3 ° C is the Nb-Ti-Cu ternary eutectic point. The eutectic point needs further study.