Anisotropic Biaxial Creep of Textured Nb-Modified Zircaloy-4 Tubing

摘要

Biaxial creep of Nb-modified Zircaloy-4 (HANA-4) tubing is investigated at varied ratios of hoop and axial stresses at a constant temperature of 500 ℃ using internal pressurization superimposed with axial load while monitoring the hoop and axial strains using non-contact laser telemetric extensometer and linear variable differential transducer, respectively. Steady-state creep rates along the hoop and axial directions were evaluated in the power-law creep regime from which the creep locus was derived at a constant energy of dissipation. The resulting creep locus was compared with that predicted by the anisotropy parameters, R and P in the Hill's formulation for generalized stress for anisotropic materials. Crystallographic texture of the tubing was characterized using electron backscatter diffraction technique. Research is supported by NSF grant #DMR0968825.