Cryogenic- and room-temperature mechanical behaviour of an AlSUB2/SUBOSUB3/SUB-fibre-reinforced high-temperature superconducting (Bi, Pb)SUB2/SUBSrSUB2/SUBCaSUB2/SUBCuSUB3/SUBOSUBx/SUBceramic matrix composite

摘要

Recently, an investigation has been reported on the processing study of a continuous Al2O3-fibre-reinforced, lead-doped Bi2Sr2Ca2Cu3Ox(BPSCCO) high-temperature superconducting (HTS) composite. In this paper, cryogenic- (77 K) and room- (293 K) temperature mechanical behaviour of the Al2O3-fibre/BPSCCO-matrix composite is studied. Tensile and notched fracture experiments are conducted on both monolithic BPSCCO and Al2O3/BPSCCO composite specimens fabricated in various hot-pressing conditions. Mechanical properties of the HTS materials are found to be strongly dependent upon processing parameters and test temperatures. Significantly higher stiffness, strength and toughness of the Al2O3/BPSCCO HTS composite are obtained than those of the monolithic BPSCCO at both room and cryogenic temperatures. Owing to the physico-chemical incompatibility and the mismatch of thermomechanical constituent properties between the matrix and the fibres, microscopic thermal stresses developed during processing and in the cryogenic environment. These effects are addressed.