Fracture toughness of Dy123 low porosity bulks at liquid nitrogen temperature

In order to evaluate the fracture toughness of DyBa2Cu3Ox (Dy123) low porosity bulks, bending tests of V-notched specimens cut from the bulks were carried out. Fracture toughness evaluations of a conventional Dy123 bulk which had pores were also carried out and effects of elimination of pores on the fracture toughness were investigated. Fracture toughness values at 77 K of the low porosity bulks were higher than those of the porous bulk. These fracture toughness values at 77 K were higher than the values at room temperature. Fracture toughness of the low porosity bulk was improved by Ag addition.

► Fracture toughness values were measured for Dy123 bulks.
► Fracture toughness was improved by reducing porosity.
► Fracture toughness values at 77 K were higher than those at room temperature.
► Fracture toughness was also improved by Ag addition.