HEAVILY COLD-WORKED HIGH-PURITY TA AS A REINFORCING STABILIZER

Mechanical and electrical properties have been studied for a heavily cold worked high-purity Ta wire. Tensile test at room temperature shows a large 0.2% proof stress of about 70 kg/mm2, which is probably caused by work-hardening in the wire drawing process. Our observations of fracture surfaces using a scanning electron microscope indicate that this material is very ductile. Moreover, this sample has a low resistivity of about 0.4-mu OMEGA cm even at the high field of 15 T. The residual resistivity ratio is about 80, which is consistent with high purity of the sample. Therefore, it has been found that the cold-worked Ta wire is applicable to a reinforcing stabilizer for conductors of large scale and/or high-field superconducting magnets.