A Simulation of the Abnormal Grain Growth in a Nano-Structural AZ31 Mg Alloy by Phase Field Model

2009 ◽  
Vol 633-634 ◽  
pp. 697-705 ◽  
Author(s):  
Yan Wu ◽  
B.Y. Zong ◽  
M.T. Wang
Keyword(s):  
Grain Growth ◽  
Phase Field ◽  
Field Model ◽  
Boundary Energy ◽  
Phase Field Model ◽  
Annealing Treatment ◽  
Interface Energy ◽  
Az31 Alloy ◽  
Abnormal Grain Growth ◽  
Interface Mobility

Abnormal grain growth was simulated by phase field model in order to find ways of producing scattered a few enormous grains in a nano-structural single phase AZ31 alloy to improve its ductility. It is shown that the abnormal grain growth is controlled by the three keys factors of interface energy, strain restored energy and interface mobility. Therefore, the microstructure with scattered a few enormous grains in the nano-structural matrix can be achieved after an annealing treatment if there is a small group of specially orientated nano-size grains in the original nao-structure with local low grain boundary energy or local high strain energy or local high interface mobility. The morphology of abnormal grains is also examined as function of annealing time to optimize the microstructure.

Phase Field Model Simulation of Grain Growth in Three Dimensions under Isotropic and Anisotropic Grain Boundary Energy Conditions

2007 ◽  
Vol 558-559 ◽  
pp. 1101-1106 ◽  
Author(s):  
Kyung Jun Ko ◽  
Pil Ryung Cha ◽  
Jong Tae Park ◽  
Jae Kwan Kim ◽  
Nong Moon Hwang
Keyword(s):  
Solid State ◽  
Grain Boundary ◽  
Grain Growth ◽  
Phase Field ◽  
Field Model ◽  
Boundary Energy ◽  
Phase Field Model ◽  
Three Dimensions ◽  
Energy Conditions ◽  
Grain Boundary Energy

Phase-field model (PFM) in multiple orientation fields was used to simulate the grain growth in three-dimensions (3-D) for isotropic and anisotropic grain boundary energy. In the simulation, the polycrystalline microstructure was described by a set of non-conserved order parameters and each order parameter describes each orientation of grains. For isotropic grain boundary energy, the simulation showed the microstructure evolution of normal grain growth. For anisotropic grain boundary energy, however, the simulation showed that certain grains which share a high fraction of low energy grain boundaries with other grains have a high probability to grow by wetting along triple junctions and can grow abnormally with a growth advantage of solid-state wetting. The PFM simulation shows the realistic microstructural evolution of island and peninsular grains during abnormal grain growth by solid-state wetting.

Phase Field Model of Grain Growth Using Quaternions

2012 ◽  
Vol 715-716 ◽  
pp. 776-781
Author(s):  
Santidan Biswas ◽  
Indradev Samajdar ◽  
Arunansu Haldar ◽  
Anirban Sain
Keyword(s):  
Grain Boundary ◽  
Grain Growth ◽  
Phase Field ◽  
Boundary Energy ◽  
Scaling Law ◽  
Phase Field Model ◽  
Polycrystalline Sample ◽  
Mechanical Processing ◽  
Grain Boundary Energy ◽  
Grain Orientations

The microstructure of a material determines its mechanical properties. Since microstructure can be tailored by thermo-mechanical processing of the metal, it is important to understand how the microstructure evolves under thermo-mechanical processing. We have constructed a phase field formalism to study recrystallization and grain growth in polycrystalline material. A unique feature of our model is that the Euler Angles (φ1,φ,φ2), obtained from Electron Back Scattered Diffraction (EBSD) data of a polycrystalline sample can be taken as an input to our model. In our model, the grain orientations at discrete grid points are represented by a non-conserved vector field, namely a quaternion. The free energy used for the evolution of the local orientations contains bulk energy for various preferred grain types and grain boundary energy. The grain orientations evolve in time following a Langevin dynamics. So far we have established that the rate of grain growth follows the usual L ~ t1/2scaling law when the grain boundary energy is independent of the misorientation angle between neighboring grains. Work on other aspects of this model is in progress.

Simulation of Ideal Grain Growth Using the Multi-Phase-Field Model

2007 ◽  
Vol 558-559 ◽  
pp. 1177-1181 ◽  
Author(s):  
Philippe Schaffnit ◽  
Markus Apel ◽  
Ingo Steinbach
Keyword(s):  
Grain Size ◽  
Grain Growth ◽  
Phase Field ◽  
Large Scale ◽  
Field Model ◽  
Three Dimensional ◽  
Phase Field Model ◽  
Two Dimensions ◽  
Von Neumann ◽  
Average Grain Size

The kinetics and topology of ideal grain growth were simulated using the phase-field model. Large scale phase-field simulations were carried out where ten thousands grains evolved into a few hundreds without allowing coalescence of grains. The implementation was first validated in two-dimensions by checking the conformance with square-root evolution of the average grain size and the von Neumann-Mullins law. Afterwards three-dimensional simulations were performed which also showed fair agreement with the law describing the evolution of the mean grain size against time and with the results of S. Hilgenfeld et al. in 'An Accurate von Neumann's Law for Three-Dimensional Foams', Phys. Rev. Letters, 86(12)/2685, March 2001. Finally the steady state grain size distribution was investigated and compared to the Hillert theory.

Sign in / Sign up

Export Citation Format

Share Document