Research On The Solidification Microstructure Simulation Of Al Alloy By Cellular Automaton Based On InteCAST Software

Numerical simulation is more and more widely used in production of casting.The results of simulation can provide scientific data support for the optimization of casting process.Research on macroscopic simulation of casting,such as temperature field,flow field and stress field has become more mature,and the application has also been a certain success.However,the performance of castings is determined by the microstructure.This paper studies the grain structure evolution of aluminum alloy castings by cellular automaton based on InteCAST software.The main works are listed as follows:Firstly,the numerical solution model of temperature field based on finite difference method is established.The methods of dealing with latent heat and boundary condition in temperature field are discussed.The continuous nucleation model based on Gaussian distribution is analyzed.At the same time,the KGT model of dendritic growth based on solute conservation is explored.Secondly,the influence of several capture algorithms on the orientation of grain growth process is discussed,and a direct capture method based on the boundary cell set is proposed.This method can avoid the overlapping of grains and other issues while dealing with the problem of grain collision.In addition,the results of grain simulation using various capture algorithms are compared,and algorithms used correction can keep the orientation while grain grows.Besides,it is also analyzed that the grain grows with directly capture algorithm under uniform and non-uniform temperature field.Then,the macroscopic temperature field is mapped into the microscopic cells by refining of the macroscopic mesh and the distance interpolation of the temperature.Simulation of the grain evolution is achieved by combining the nucleation and growth model of microstructure in the process of aluminum alloy casting solidification.In addition,the casting experiment is designed and executed,through the thermocouple temperature measurement and metallographic comparison,to verify the correctness of the coupling program.Finally,the casting of a casting company is simulated and analyzed by using the coupled coupling program.The temperature distribution of the aluminum alloy casting in the solidification process,the temperature curves and the grain simulated structure at different wall thickness are analyzed.The grain structure at the thin wall is smaller than that at the thick wall and has a large grain density.The coupling process can be used to qualitatively and quantitatively analyze the grain structure of aluminum alloy castings,and the casting process of castings can be optimized and improved according to the relevant information of castings.