Use Phase-field To Simulate On The Evolution Of The Foamed Aluminum Made By The Gas Injection Method

As a representative of metal foam material, foamed aluminum, which has been usedwidely in the fields of spaceflight, architectural structure and automobile, is a promisingfunctional and structural material. Because of its outstanding thermal, acoustical andmechanical performances, foamed aluminum has become a hotspot of research anddevelopment in the material science and technology. There are many approaches tomanufacture cellular metallic materials. From which the gas injection method has specialadvantages in the respect that metallic foams can be produced continuously and their size islittle limited. In order to explore approaches through which one can effectively control themanufacture process and the performance of aluminum foams, it is necessary to investigateand understand deeply factors affecting the foaming process. In this thesis, hydrodynamicbehaviors of metallic foam flow and bubble moving and distribution characteristics in themelt were systematically studied by numerical simulation, and on this basis some insightsinto effects of relevant parameters on the foam structure have been gained. The main worksand conclusions are summarized as follows:In this thesis, the Two-dimensional simulation was used for studying the evolution ofmetal bubble organization by phase-field method. Phase-field method is a kind of analogymethods based on classical thermodynamics and kinetic theory which established byGinzburg-Landau theory. The comprehensive functions of Ordering potential and theThermodynamic driving force were considered for establishing Phase-field equations, whichintroduced the variables of phase-field. The Phase-field equations could describe the form ofsolid liquid inter-phase and the movement of interface. We write a matlab program,establish a series of integrated simulation methods and find well anastomotic resultbetween simulation and experiment through comparison with bubbles during realproduction process, consequently confirm the feasibility of phase-field method. Then wediscuss the influence of the number of orientation field variable, boundary energy andmigration rate to bubbles evolution.