Abstract
The aim of this thesis is to examine how the die design influences the microstructure, texture, and mechanical properties of extruded aluminum and magnesium flat products. Aluminum and magnesium are both lightweight metals. Aluminum, with a density of 2.7 g/cm³ and a face centred cubic (FCC) crystal structure, offers excellent ductility and corrosion resistance, making it ideal for applications in the aerospace and construction. Magnesium is lighter at 1.74 g/cm³ with a hexagonal close packed (HCP) structure and is preferred for applications in the automotive and aerospace industries, although it is less corrosion resistant and more difficult to form at room temperature.
The objective is to understand how the die design influences the mechanical anisotropy of the direct extruded parts by altering the material flow at the die inlet during extrusion. Specifically, the study is involving billets at temperatures of 350°C for the magnesium alloys, Al-Zn containing and Zn-Ca containing Mg-Alloys (AZ31, ZX10), and of 450°C for the aluminum alloy, Mg-Si containing (AA6082). They were extruded at a speed of 1 mm/s using five different dies: conventional, friction, even, modified and hill dies. The conventional die is used as a standard die. The friction die increases the friction zone between the die and the material. The modified die changes the material flow through deflection, while the even die reduces the deflection and the hill die increases the deflection.
The microstructure and texture of each extruded component are examined along the extrusion direction, at two positions: the edge and the center, using scanning electron microscope SEM. To further evaluate the material behavior, tensile tests are performed on the extruded flat bands to evaluate the mechanical properties. The results were provided information on how variation in die design affect the anisotropy and homogeneity of the extruded flat bands.
