When The Deformation Of The Semi-solid State Of Al-4cu-mg Alloy Microstructure Evolution

During the semi-solid forming, the microstructure in materials undergoes a series of dynamic changes, which will affect the deformation behavior of materials and servicing properties of workpieces. To understand the effects of process parameters on microstructure variables, and explore the deformation mechanism and establish the model for microstructural evolution in the semi-solid forming can provide the theoretical and technological foundation for optimizing the process parameters and developing the semi-solid technique.Effect of the process parameters, including deformation temperature, height reduction and strain rate, on microstructure variables, including the grain size and the fractal dimension, has been investigated by the isothermal compression and quantitative metallography examination. The distinctions of microstructure between the semi-solid forming and high temperature deformation of the Al-4Cu-Mg alloy as received and semi-solid Al-4Cu-Mg alloy has been investigated. Meanwhile, the semi-solid deformation mechanism has been investigated by TEM and SEM, and the defective structure, including cavity, liquid phase segregation and constituent segregation, has been investigated.In the end, integrating the advantages of the fuzzy set and the artificial neural network theory, a microstructural evolution model during the semi-solid forming has been established according to the experimental results. Meanwhile, the present model is checked. The comparison of the calculated results with the experimental of the test samples shows that the maximun error of grain size is less than 10%, and which of fractal dimension is less than 15%. The microstructural variables of Al-4Cu-Mg alloy has been calculated during semi-solid forming.