| 초록 |
The discovery of the superconductor MgB2 with a transition temperature near 40 K has promoted a new interest in the area of fundamental and applied research on superconducting materials. A large number of articles dealing with the physical and metallurgical properties of this compound have been published in a few months. The behavior of the physical properties of MgB2 is intermediate between that of conventional and of high Tc systems. For manufacturing an MgB2 superconductor in the solid state, by mixing Mg and B powders with a suited volume ratio, prior to compress at cold or hot condition, finally manufactured through plastic working process such as pressing or extrusion process. The specific laminated with a joining process of more than one that has been prepared of the shape of the non-metal material and the metals is utilized. In the previous method of fabrication, techniques that utilize powders, since through a plurality of unit processing steps of dispersing the materials having a large difference of their characteristics and physical mixing, the process is complicated, and leads to non-uniform dispersion of Mg and B powder. It is difficult and hard to reach a uniform ideal physical property in the coherence problems. In the present study, we exposed Mg-B/Nb/Cu cladding to hydrostatic extrusion process. The aim of this study is to investigate the differences in microstructure and texture evolution of Nb materials in Mg-B/Nb/Cu cladding as a function of extrusion ratio. For mechanical properties, hardness measurement has been carried out. For microstructure observation and texture evolution of Nb and Cu layer, electron backscatter diffraction (EBSD) were carried out in the present study. |
