Depth-sensing indentation study of superconducting MgB2 wire

Abstract Superconducting MgB 2 composite wire was prepared by packing blended MgB 2 inside of Cu tubes using the powder-in-tube (PIT) method. Mechanical properties of the sample were then characterized by using a dynamic ultra-micro indentation experimental technique. The hardness ( H ) and the elastic modulus ( E ) values were calculated by the method of Oliver and Pharr. It was found that both the hardness and the elastic modulus exhibit significant peak load dependence (i.e., indentation size effect (ISE)). The experimental h f  /  h max values, lower than the critical value (0.875), indicate that the MgB 2 wire shows work hardening behaviour.