High-strain rate behavior of nanostructured niobium processed by severe plastic deformation to very large strains Conference Paper uri icon

abstract

  • In this work, we have investigated the high-strain rate, uni-axial compressive behavior of nanostructured niobium (Nb), a refractory metal with body-centered cubic (bcc) lattice structure. The material was processed by equal channel angular extrusion (ECAE) to a maximum of 24 passes via route E. The microstructure of the processed billets was analyzed using electron back-scattering diffraction (EBSD). Microstructural analysis including grain size and texture studies showed the resultant microstructure to be nanocrystalline (< 400 nm) and of homogeneous texture after 24 passes. To examine the mechanical properties of the ECAE-nanostructured Nb, mechanical testing within a wide range of strain rates from quasi-static loading (strain rate <1.0 s-1) to high rate (strain rate > 103 s-1) loading was performed. Nanostructured Nb was observed to exhibit homogenous plastic flow, with only minor and diffuse adiabatic shear localization under high-rate uni-axial compression. Flow softening is primarily caused by uniform adiabatic temperature rise of the whole specimen combined with such diffuse shear localization.

author list (cited authors)

  • Pan, Z., Ying, W., Wei, Q., Xu, F., Zhang, X., Hartwig, K. T., Kecskes, L., & Mathaudhu, S.

publication date

  • December 2011