Nanohardness and Young's modulus of YBCO samples textured by the Bridgman technique

摘要

Mechanical properties of the orthorhombic phase of YBa2Cu3O7-delta ( Y123) at room temperature have been investigated at different applied loads: 5, 10, 30 and 100 mN using a nanoindentation technique. This study was carried out for different monodomains on the ( 001) plane for textured Bridgman samples with dispersed particles of Y211 as pinning centres. Hardness and Young's modulus values were calculated using the Oliver-Pharr approach. Nanohardness and Young's modulus for the Y123, Y2BaCuO5 ( Y211) and Y123/ Y211(composite) ( YBCO) were determined using an applied load of 5 and 10 mN. For higher loads, it is not possible to differentiate the matrix ( Y123) from the precipitates ( Y211). In this case, only hardness and Young's modulus of the YBCO composite can be determined. Finally, the ultra-low load imprints obtained by nanoindentation have been correlated with parameters obtained by atomic force microscopy ( AFM) and field emission scanning electron microscopy ( FE-SEM).