Tensile superplastic deformation of YBa2Cu3O7−x high-TC superconductors Original Research Article

The superplastic behavior of polycrystalline YBa2Cu3O7−x was investigated. Tensile elongations above 85% were achieved for fine-grained (<1 μm) microstructures tested in the temperature range of 800–875°C and strain rates varying from 6×10−6 to 10−3/s. It is suggested that the dominant superplastic deformation mechanism is grain boundary sliding accommodated and controlled by interface reaction, characterized by a stress exponent of n=2, a grain size exponent of p=1.5, and an activation energy of Qsp=515±104 kJ/mol. A Langdon–Mohamed deformation mechanism map was constructed. Overlaying the available experimental data onto the map, including the results from creep studies, gives an insight into the deformation mechanisms involved in high-temperature deformation of YBa2Cu3O7−x.