Local deformation distribution and evolution of 25cr2ni2mov welded joints under uniaxial tensile loading

Abstract This study addresses the issue of deformation mismatch caused by material heterogeneity in welded rotors of nuclear turbine generators. Focusing on a novel narrow-gap TIG/SAW hybrid weld joint of 25Cr2Ni2MoV steel, a multiscale investigation into the deformation mechanism was conducted. Mechanical properties of the steel were characterized through nanoindentation and uniaxial tensile tests, revealing the gradient distribution of mechanical properties across the weld joint. By integrating microscopic strain field evolution analysis, the study establishes a critical correlation between localized deformation concentration at heterogeneous interfaces and macroscopic instability failure.