An analysis of microstructural and thermal softening effects in dynamic necking Articles uri icon

publication date

  • January 2015

start page

  • 298

end page

  • 310

volume

  • 80

international standard serial number (ISSN)

  • 0167-6636

electronic international standard serial number (EISSN)

  • 1872-7743

abstract

  • The competition between material and thermal induced destabilizing effects in dynamic shear loading has been previously addressed in detail using a fully numerical approach in Osovski et al. (2013). This paper presents an analytical solution to the related problem of dynamic tensile instability in a material that undergoes both twinning and dynamic recrystallization. A special prescription of the initial and loading conditions precludes wave propagation in the specimen which retains nevertheless its inertia. This allows for a clear separation of material versus structural effects on the investigated localization. The outcome of this analysis confirms the dominant role of microstructural softening in the lower strain-rate regime (of the order of 10(3) s(-1)), irrespective of the extent of prescribed thermal softening. By contrast, the high strain-rate regime is found to be dominated by inertia as a stabilizing factor, irrespective of the material's thermo-physical conditions, a result that goes along the predictions of Rodriguez-Martinez et al. (2013a) regarding dynamically expanding rings. (C) 2014 Elsevier Ltd. All rights reserved.

keywords

  • 2-phase titanium-alloys; high-strain rates; ductile rings; plastic-flow; recrystallization; shear; localization; identification; fragmentation; deformation