Plastic deformation of ITER specification tungsten Temperature and strain rate dependent constitutive law deduced by inverse finite element analysis

In this work, we have derived a constitutive law describing the elasto-plastic response of tungsten by applying an inverse finite element analysis (IFEA) to grasp the deformation well beyond the onset of deformation instability in tensile tests. A model based on the Kocks-Mecking representation of thermally-activated dislocation-mediated plasticity was applied to characterise the mechanical response of tungsten compliant with the ITER specification. The developed model accurately describes the temperature and strain rate dependent tensile properties in the temperature range 250–600 ◦C. The capability to extrapolate the hardening law to a higher temperature and strain rate range is demonstrated. A particular advantage of the developed method is its applicability to neutron irradiated materials, for which the uniform elongation is often very low or even negligible.