“…In these, analytical solutions can no longer be derived, and numerical tools such as finite-element and finite-difference methods are applied. Lacoste et al [15] presented a model for the infiltration of aluminum into a preform. A one-dimensional model was compared with existing analytical solutions and solved as well.…”
In the pressure infiltration process of metal-matrix composites, molten metal is injected under external pressure into a porous preform of the reinforcing phase and solidified, either during infiltration or after the mold is filled. To simplify the problem, the assumption of isothermally saturated fibrous preform with molten metal is adopted. The flow of molten metal is a moving boundary phenomenon which is similar to a fluid flowing through a porous medium. A numerical technique, body-fitted finite element method (FEM), is used to generate grids inside the physical domain and to calculate the distribution of pressure and other relative properties. Results show that the injection flow rate exponentially decreases with the infiltration time. Increasing injection pressure can effectively reduce the infiltration time. A simple and practical prediction of infiltration time under the various parameters is also provided in this study.
“…In these, analytical solutions can no longer be derived, and numerical tools such as finite-element and finite-difference methods are applied. Lacoste et al [15] presented a model for the infiltration of aluminum into a preform. A one-dimensional model was compared with existing analytical solutions and solved as well.…”
In the pressure infiltration process of metal-matrix composites, molten metal is injected under external pressure into a porous preform of the reinforcing phase and solidified, either during infiltration or after the mold is filled. To simplify the problem, the assumption of isothermally saturated fibrous preform with molten metal is adopted. The flow of molten metal is a moving boundary phenomenon which is similar to a fluid flowing through a porous medium. A numerical technique, body-fitted finite element method (FEM), is used to generate grids inside the physical domain and to calculate the distribution of pressure and other relative properties. Results show that the injection flow rate exponentially decreases with the infiltration time. Increasing injection pressure can effectively reduce the infiltration time. A simple and practical prediction of infiltration time under the various parameters is also provided in this study.
“…In these, analytical solutions can no longer be derived, and numerical tools such as finite element and finite difference methods are applied. Lacoste et al (1991Lacoste et al ( , 1993 proposed a model based on finite volume formulation to simulate the flow and the solidification of a liquid metal. Tong and Khan (1996) developed a numerical finite difference model: the mold walls were insulated, only heat exchange between fibers and metal was taken into account.…”
“…However, several papers show or qualitatively describe deformation of the solid preform [4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19] (see also [20] for a recent review of the subject).…”
This paper deduces a new model aimed at simulating injection molding processes under isothermal conditions. These processes can be generally stated as infiltration problems in initially dry porous materials. The spatial domain is then divided by the infiltration front into two time-dependent subdomains, the dry and the wet porous preforms, both being allowed to deform under the action of the liquid pressure. It is shown that the model calls for the definition of the stress-deformation relationship of both the dry and the wet preforms, which are assumed to behave elastically and inelastically, respectively. The coupled flow/deformation problem in the two regions (separated by an interface) is formulated with the corresponding boundary conditions and with the proper evolution equations determining the motion of the boundaries.The mathematical problem is solved numerically, highlighting the importance of inertial terms in the early stage of the infiltration and focusing on the influence of the mechanical properties of the material and on the deformation of the preform during the infiltration process.
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