ALBERT

Notes: Purpose - To study heat transfer kinetics at the fiber scale in order to describe injection of liquid metal through a fibrous perform initially situated in a preheated mould, which is one of the various methods used in order to produce metal matrix composite materials (MMCs). Design/methodology/approach - The first part presents a preliminary study in a static case to describe heat transfer kinetics between a fiber and the matrix in the case of a sudden contact of both components initially set up at different temperatures. This model enables to study the influence of the various parameters of the problem on heat transfer kinetics with phase change. In the second part, we present a modeling which takes into account the metal convection within the pores of the preform. Findings - The numerical results of these two models justify the instantaneous thermal equilibrium assumption classically admitted to describe MMCs manufacturing methods. The results of this dynamic microscopic model are compared with the results issued from a single temperature macroscopic model to justify the methodological approach and the choice of the microscopic domain geometry representative of the MMCs manufacturing process. Research limitations/implications - This first numerical model at the microscopic scale deals with the study of heat transfer between fibers and a pure metal. Next step will be the extension of this study to the preform infiltration by a metal alloy. Injection of matrix alloy implies the appearance of phenomena generated by segregation during phase changes. Originality/value - The results of simulation tests, making use of the usual conditions of MMCs processing, show pretty good agreement with those of macroscopic models describing the anisothermal flow of a pure metal through a porous medium. From this coherence and from the results of the microscopic models as well, the hypothesis of instantaneous thermal equilibrium between fibers and metal (widely used in the literature to study the production of MMCs by infiltration of the liquid metal through the fibrous reinforcement) is justified. Moreover, it will be possible to extend it to the study of infiltration by an alloy, taking then into account thermal and solutal coupled transfers inside the study domain defined in the present work.