Nowadays, the finite element method is still the first choice of researchers in metal extrusion analysis. However, recent published papers have also supported that metal plastic flow can be modelled by the flow formulation, employing the finite volume method. In this work, the numerical scheme presented by Martins et al. [16] based on finite volume method together with the explicit MacCormack numerical method, was used to analyse aluminum axisymmetric direct extrusion in a 90° die. A structured, fixed and collocated mesh and numerical convergence based on the SIMPLE method were employed to attain pressure-velocity coupling. The main goal of present numerical scheme was to obtain the axial and radial velocities and pressure distributions. From these results, it was possible to obtain and identify the dead zone inside the billet deformation region in direct extrusion of aluminum in a 90° die. The field variables results shown in present work had good agreement when compared with those from literature.

In the aluminum die casting process, erosion, corrosion, soldering, and die sticking have a significant influence on tool life and product quality. A number of coatings such as TiN, CrN, and (Cr,Al)N deposited by physical vapor deposition (PVD) have been employed to act as protective coatings due to their high hardness and chemical stability. In this study, the wear performance of two nanocomposite AlTiN and AlCrN coatings with different structures were evaluated. These coatings were deposited on aluminum die casting mold tool substrates (AISI H13 hot work steel) by PVD using pulsed cathodic arc evaporation, equipped with three lateral arc-rotating cathodes (LARC) and one central rotating cathode (CERC). The research was performed in two stages: in the first stage, the outlined coatings were characterized regarding their chemical composition, morphology, and structure using glow discharge optical emission spectroscopy (GDOES), scanning electron microscopy (SEM), and X-ray diffraction (XRD), respectively. Surface morphology and mechanical properties were evaluated by atomic force microscopy (AFM) and nanoindentation. The coating adhesion was studied using Mersedes test and scratch testing. During the second stage, industrial tests were carried out for coated die casting molds. In parallel, tribological tests were also performed in order to determine if a correlation between laboratory and industrial tests can be drawn. All of the results were compared with a benchmark monolayer AlCrN coating. The data obtained show that the best performance was achieved for the AlCrN/Si3N4 nanocomposite coating that displays an optimum combination of hardness, adhesion, soldering behavior, oxidation resistance, and stress state. These characteristics are essential for improving the die mold service life. Therefore, this coating emerges as a novelty to be used to protect aluminum die casting molds.

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