The study relates to a process of continuous rotary extrusion (CRE), also known under the name of a Conform Process. This method is used more and more extensively for the plastic working of metals and alloys. In CRE, the feedstock is fed into a profiled groove on the rotating extrusion wheel and is pressed by the pressing wheel. The friction of the extruded material against the rotating wheel generates a force that is pushing the material into the deformation chamber followed by extrusion through the die orifice. The extrusion by CRE was performed on an MC-260 device supplied by Meltech-Confex and installed at IMN - OML for processing of the 6063 aluminium alloy. The feedstock was composed of annealed rods. Two parameters were controlled during extrusion: the temperature of the shoe (element of the housing pressing the extruded material to the wheel) and the speed of the driving wheel. The 6063 alloy was extruded using the wheel speed of 2, 5, 10 and 15 rpm and the shoe temperature of 90°C and 105°C. The extruded flat sections were examined visually for continuity and quality of the resulting surface. In the feedstock rod and in the extruded flat sections (before and after heat treatment), the microstructure and grains were examined by light microscopy. Mechanical properties were also determined (static tensile test and hardness measurement). The study shows how the structure and the mechanical properties of the extruded flat sections are changing depending on the extrusion parameters applied. From the 6063 alloy rods extruded by CRE, flat sections of satisfactory quality were obtained. It was found that CRE yields the highest mechanical properties combined with the correct structure and high surface quality when the feedstock is extruded with the wheel rotational speed of 10 rpm and the shoe temperature of 105°C.
The article presents the change in mechanical properties of AlZn9Mg2.5Cu1.8 alloy resulting from the process of solution heat treatment and aging. The heat treatment was performed on a unique UMSA (Universal Metallurgical Simulator and Analyzer) device. The aim of the study was to determine optimum heat treatment parameters for the tested alloy of ultrafine grain structure obtained by Rapid Solidification (RS). To achieve this purpose, heat treatment to the T4 and T6 condition was carried out. The solution heat treatment was carried out at a constant temperature of 460 °C for 2 hours, while the time - temperature parameters of the aging process varied. The treatment undertaken resulted in improved mechanical properties.
Heat treated aZ61 MagnesIuM alloy obtaIned by dIrect extrusIon and contInuous rotary extrusIon processThe results of studies carried out on the heat treated AZ61 magnesium alloy extruded by two methods, i.e. direct extrusion and continuous rotary extrusion, were presented. As part of the work, parameters of the T6 heat treatment were proposed and aging curves were plotted. The solution heat treatment process was accompanied by the grain growth. During artificial aging, due to the decomposition of solid solution, the β-Mg17Al12 phase was precipitated from the supersaturated α solution. It precipitated in a coagulated form at the grain boundaries and in the form of fine-dispersed plates arranged in a preferred direction relative to the grain orientation. Rods obtained by continuous rotary extrusion, unlike those made by the direct process, exhibited a low degree of texturing and lack of anisotropic properties.
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