Evaluation of the mechanical properties of CICC jacket for CFETR superconducting magnet

Abstract

Modified 316LN and JK2LB stainless steel were selected as candidate jacket materials for superconducting cable in conduit conductors (CICC) of the China Fusion Engineering Test Reactor (CFETR). Different superconducting conductors need to undergo different cold working deformations and different heat treatment processes during the manufacturing process. Therefore, a systematic investigation was done to examine the influence of different cold working deformations and different heat treatment processes on the mechanical properties of the two materials. The mechanical properties of materials were measured at 4.2 K, 77 K and 300 K, and Young's modulus, yield strength (0.2% offset), ultimate tensile strength and elongation at failure were reported. In addition, the fracture morphology of all tensile samples was observed by backscattered-electron imaging (BSEI). The results show that the effect of increasing cold deformation of extrusion to improve the yield strength of the jacket is not obvious. In addition, the heat treatment schemes of different superconducting materials have limited influence on the performance of the jacket. These two materials have the potential to be used in CICC conductors prepared from different superconducting materials.