Multi-phase field simulation of multi-grain peritectic transition in multiple phase transformation
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https://doi.org/10.1007/s41230-020-9136-0
Multi-phase field simulation of multi-grain peritectic transition in multiple phase transformation *Li Feng1, 2, Jun-he Zhong1, Chang-sheng Zhu2, Jun Wang1, Guo-sheng An1, Rong-zhen Xiao1, 2 1. College of Materials and Engineering, Lanzhou University of Technology, Lanzhou 730050, China 2. State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China
Abstract: Taking Fe-C binary alloy as an example, based on the multi-phase field model, the nucleation and growth of δ phase, peritectic reaction, peritectic transformation, and the growth of subsequent austenite are simulated. Effects of the nucleation site of austenite on the peritectic reaction rate and the starting time of the peritectic transformation were studied. The simulation results show that the γ phase, as a shell, surrounds the δ phase and grows rapidly when the peritectic reaction occurs between the dendritic δ grains, and a layer of γ phase shell is formed around δ phase after the peritectic reaction. After the δ phase is surrounded by γ phase completely, the membrane shell separates the L phase from the δ phase, so that the phase transfers from peritectic reaction to peritectic transformation. During the peritectic transformation, since the solute diffusion coefficient of the liquid phase is much greater than that of the solid phase, the average growth rate of austenite in the liquid phase is visibly higher than that of the δ phase. The peritectic reaction rate is related to the curvature of the nucleation site of the γ phase on the δ phase grains. The peritectic reaction rate at the large curvatures is faster than that at small curvatures. Key words: phase field; Fe-C binary alloy; peritectic transformation; microstructure; numerical simulation CLC numbers: TP391.9
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icrostructure determines the mechanical properties and service life of the castings, which makes it of great significance to effectively control the formation of microstructure in the forming process of the casting. This is a complex process, involving high temperature heat transfer, convection diffusion, solute diffusion, and the interaction between metal and mold, which is difficult to control and observe directly [1,2]. With the rapid development of computer software and hardware technology, the computer numerical simulation of the solidification process has become an important method for the research of solidification microstructure [3]. The phase field method is one of the common numerical simulation methods. The advantage of the phase field method is that there is no need to track complex solid/ liquid interface, and it is easy to couple with other external fields. The physical parameters of materials can be effectively expressed in the model in the form of phenomenological parameters, and the evolution of the solid/liquid interface and dendrite growth morphology *Li Feng Male, born in 1981, Associate Professor. His research interests mainly focus
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