Mechanical Characterization and Modeling of a Powder-In-Tube MgB₂ Strand

Abstract

The strain dependence of superconducting material is known to be responsible for the degradation of the electrical performance of cables. As such, their electrical optimization requires an understanding of their mechanical behavior. The present paper introduces a method for elasto-plastic modeling of commercial MgB2 multi-filamentary strands manufactured by the ex-situ powder-in-tube method. The model is based on a simplified representation of the structure, built using components' volume fractions and nano-indentation test data. Monotonic and cyclic tension-compression tests were performed on the strands before and after chemical dissolution of the Monel outer layer to provide a multi-scale experimental database. These tests were used to identify the parameters of the kinematic and isotropic hardening laws of the elasto-plastic model. The model intends to be subsequently used to simulate the electrical behavior of cables and define guidelines for the manufacturing process, cabling process and end-product operating condition.