Impact of tungsten recrystallization on ITER-like components for lifetime estimation

For ITER divertor, plasma facing components are made with tungsten as armor material. In previous papers, it has been shown that plasma facing components are prone to crack, appearing in tungsten block during thermal cyclic heat loading. In order to predict component lifetime, a numerical simulation is proposed in this paper. With regard to previous studies, tungsten (raw and recrystallized) real mechanical behaviors are taken into account. To be used as inputs for numerical simulations, compressive tests at different temperatures and strain rates were realized on raw and recrystallized tungsten. Raw tungsten tests reveal a linear elastic and ideal plastic behavior that is sensitive to strain rate. Concerning recrystallized tungsten, an elastic-viscoplastic behavior is observed on the entire explored temperature range (up to 1150 degrees C), that can be described by an elastic-plastic model with kinematic hardening. Manson-Coffin relationships are used to estimate the lifetime. When taking into account real mechanical behaviors for raw tungsten and recrystallized tungsten, we show that lifetime estimation is mainly driven by recrystallized thickness in the component, by the ductile to brittle transition temperature and finally by strain rate.