Numerical Simulation On Aluminum Alloy Semi-Solid Electromagnetic Stirring And Experimental Research

Semisolid metal forming (SSM or SSF) has an extensive applications in manyindustries, especially in the automobile industry and higher theoretical researchingvalue as the formed parts possess more compact microstructure, less entrapment ofgas and better mechanical properties, meanwhile it belongs to net shape forming andadvanced materials manufacturing technique, and it also strides many fields, such asheat transfer, fluid mechanics, materials mechanics and computer mathematics etc.Aluminum alloy is the most suitable materials for the semi-solid forming and for thereduction of vehicle weight because it has a series of advantages, such as less density,higher strength to mass ratio and Baser reutilization etc.As the purpose of this research, the processing parameters will be optimized toobtain the suitable semi-solid slurry of ZL107 alloy through the simulation of fluidfield with computer. The kinetic characteristic and rule of the fluid during theprocess of electromagnetic stirring will be found with the experimental research.Firstly, the modeling and simulation of the coupling of the electromagnetic fieldand the fluid field of electromagnetic stirring were done, and then the distributing ofthe electromagnetic field and the fluid field were obtained through the simulation.Line of magnetic induction is densest near the coil from the distributing result of theelectromagnetic field. Line of magnetic induction' density reduces gradually fromthe melting surface to the inner melting. Because the line of magnetic induction'density and the intensity of magnetic field are direct proportion, the intensity ofmagnetic field gradually reduce from the melting surface to the inner melting. Twoequal swirls distributed in the melting area lengthways from the result of thesimulation, and it was correct because it accorded with the principle and theexperiment of the electromagnetic stirring. The max flowing velocity of the innermelting presents to the top right corner and the bottom of right corner of the meltingarea. The biggish flowing velocity presents to some nodes. The flowing velocity isvery equilibrium in the other area. The least flowing velocity of the inner meltingpresents to the central area. The elementary alteration rule of fluid field is beenanalyzed with the alteration of stirring frequency, current density, stirring time, stirring temperature and fluid viscosity.The device and parameters of the experiment are confirmed. Melt ZL107 andstir the melting in the electromagnetic field with different stirring frequency andcapacity. Observe the micro structure of the materials that gets from the differentstirring technology. With the action of the electromagnetic force, intensiveconvective movement generate in the inner melting. Pine-tree crystal was broken.Because of the collision and friction between the crystal grains, the crystal grainbecomes round, the structure gets tight, and meets the necessity of semi-solid slurrypreparing. When stirring frequency and capacity enlarge, the electromagnetic forceof stirring get heavier, the structure become more tight, the crystal grain get moreround.