Shock-induced phase transition of iron studied with phase field method

Q Zhang ,D Zhao ,X Guo ,Zhi Wang

doi:10.21152/1750-9548.12.2.131

Q Zhang , D Zhao + Show 2 more

Open Access

https://doi.org/10.21152/1750-9548.12.2.131

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Abstract

To develop phase field method in high strain rate loading, it derived the governing equations of phase field model in the foundation of entropy functional, and the model adopted a diffusion interface, which made automatic tracking on interface possible. Added the order parameter to characterize the different phases of materials, and simulated the soften and phase transition in shock-induced loading. According to the conservation theorems and principle of entropy increasing, we established the governing equations of shock-induced phase transition in metal dielectric. Then the work discretized phase field model by using high order difference scheme, introducing the artificial viscosity, and obtained the numerical solution of the phase field model. Compared the numerical value with the theoretical solution, the accuracy of the developed phase field model was verified. Based on the model described above, the work study the a®e polymorphic phase transition of iron-base alloy induced by one-dimensional shock wave. Considering the spatial and temporal distribution of each parameter field and the Hugoniot data for iron, it further analyzed the coupling effect of wave and phase transition by tracking the changes of pressure and speed in each unit. The simulation results fitted well with the experimental results, which indicated that the phase field model developed was successful, and it would help people to understand the microstructural evolution of metallic materials under the shock wave.

Highlights

In the study of solid-solid phase transition in the metal on the impact loading, it is representative and focused attention wildly that the α ↔ ε polymorphic phase transition of iron base material
The martensite phase transition of iron-base alloy under shock wave loading is the main objective of this paper, so we need to establish a shock wave propagation model, which is suitable for the phase field method
Considering the relation of shock wave velocity DD and particle velocity after wave uupp under different pressures, it can be seen from the Fig.4 that the results obtained through the simulation of the phase field model, which was established by us, are in good agreement with the experimental results

Summary

INTRODUCTION

In the study of solid-solid phase transition in the metal on the impact loading, it is representative and focused attention wildly that the α ↔ ε polymorphic phase transition of iron base material. [4]) introduced a phase field model based on entropy functional. [5]) deduced the general phase field model of pure substance based on entropy function. The martensite phase transition of iron-base alloy under shock wave loading is the main objective of this paper, so we need to establish a shock wave propagation model, which is suitable for the phase field method. We study the variation rules of phase change pressure threshold, and relaxation time of phase transition under different pressures

PHASE FIELD MODEL

RESULT

Phase Transition Relaxation Time

Interface Parameters

CONCLUSION