A model for plastic deformation and phase transformations of zirconium under high-rate loading

Abstract

A constitutive model which considers both plastic deformation and solid–solid phase transformations has been developed for zirconium under high-rate loading. Within the multiphase mixture regime, a lower-bound (Ruess) or uniform-stress assumption is used. It also is assumed that coexisting phases are in thermal equilibrium. The plastic deformation of the mixture is given by the contributions of individual phases. Each phase has a separate plastic yield surface, which evolves (strain-hardening) according to the plastic strain accumulated in the phase. A novel, fully implicit numerical algorithm for the plastic response of multiphase materials with separate yield surfaces is developed. The model is validated using data for plate impact experiments on a zirconium target. Simulations also are provided to demonstrate the ability of the model to capture the relevant aspects of the high-strain-rate deformation of a zirconium plate loaded with explosives. The numerical results indicate that the phase histories of the material under a general, three-dimensional (3D) stress state can be very complicated and cannot be anticipated without a detailed 3D calculation including the effects of phase transformations. The results presented here may have an important implication in designing systems involving zirconium for high-rate applications.

A Multi-Phase Modeling Framework Suitable for Dynamic Applications

“…A generalization of this latter assumption would be that of uniform stress, including both pressure and deviatoric portions of the stress, in which case the plastic strain rates would not be identical. The uniform constituent stress approach has been previously used, for example in [12,30,31]. However, the uniform plastic strain rate assumption is simple and computationally efficient.…”

Kinetics of Zr under shock-ramp compression

“…α-ω相变压力有影响, 而对于ω-β相变压力无影响. 肖 大武 [13] 、李英华 [14] 和种涛等人 [15,16] 相变速率模型采用唐志平 [28] 在Hayes [29] 模型基础 [16,30] 为…”

Atomistic Insight into the Defect-Induced Tunable Plasticity and Electronic Properties of Tetragonal Zirconia

“…Nevertheless, most of the conducted research has focused on stabilizing [46] and controlling the size and shape [47] of defective zirconia. However, there has been little attention paid to the effect of oxygen vacancies and nitrogen dopants on atomic displacement [48] and deformation behavior [49]. The depth-sensing nanoindentation test is a popular way to probe the deformation behavior of a broad range of materials on an adequately small scale [50][51][52][53].…”