The aluminum alloys are ideal material because of their corrosion resistance, recycling ability, high specific strength and especially low density for lightweight structures of transportation, aerospace, automotive industries. Hot extrusion process is the most used metal forming method for obtaining a variety of aluminum alloy profiles. The demand for large cross section, multi cavity and thin wall profiles has been increasing with the development of the industry and extrusion method is key solution for producing complex profiles with high productivity. These profiles are generally extruded by porthole dies. The extrusion process by porthole die is complicated and die design has great importance for the quality of the extruded product. Design of the porthole die should give optimum material flow and homogenous temperature distribution both for obtaining desired profile and eliminating die scrap. The measuring the temperature and material flow is not possible for closed die formation and it is so important to estimate both material flow, temperature change in the die. For this aim, an extrusion simulation of a porthole die for standard aluminum profile was investigated in this study with the support of HyperXtrude Inspire Extrude Metal 2019 software, which is specialized for FEM calculations of extrusion process. Each step of extrusion process was simulated. Aluminum AA6063 material was used for simulations, the process temperature was 4500 °C and punch velocity was selected as 5 mm/sec. Finally, the FEM results were obtained and the temperature distribution, pressure distribution, billet interface and relative die exit speed results were analyzed.

A new concept of solid-solid mass diffusion fin was introduced in this paper. The authors described the mass diffusion in fluid flows to analyze the transfer process in solids and its applications, especially in metallurgical research. Using the advantage of the similarity between heat transfer and mass diffusion transfer will make this issue more practical. The authors suggested a new approach to determine the maximum mass diffusion transfer between two solids by implementing of the extended surface on each solid, where the optimal mass diffusion between solids is required. Then, meshing the surfaces together in order to increase the transfer efficiency was carried out. A complete analysis of the extended surfaces design (diffusion fins), its efficiency and effectiveness were presented. Moreover, mathematical models of each consideration were constructed. The authors found that the total surface efficiency increased along with the number of mass diffusion fins attached to the base, but its effectiveness did not. The mass diffusion for an extended plate increased the total mass diffusion transfer between two materials.