چكيده به لاتين
Nowadays, due to the growing need of the industry for materials with the right mix of mechanical and chemical properties, the 5xxx series non-heat treatable alloys are used in industries such as the marine, aerospace and military industries as well as in the manufacture of water structures, tankers and pressure vessels. The AA5083 alloy has the highest mechanical properties among all 5xxx series alloys. The strengthening mechanism in these alloys is controlling the grain size, hardness, and solid solution of magnesium in aluminum. As a result of heat treatment, these atoms are removed from the solid solution and precipitate β (Al3Mg2) in the grain boundaries becomes more susceptible to boundary corrosion in addition to decreasing strength. Both Age softening and strain ageing have made the use of these alloys difficult. In this study, while determining the optimum thermomechanical cycle of the AA5083 alloy, the application of H34 thermomechanical operation, which is a combination of cold rolling and annealing stabilization, investigated the influence of temperature, time and heating rate on the microstructure and mechanical properties of the alloy. For this purpose, optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction analyzer (XRD), Brinell hardness (HB), cold tensile test and infrared heat furnace were used. Also in order to determine the optimum stabilization conditions and to compare the corrosion resistance, NAMLT was used and Finally, the microstructure and mechanical properties of the stabilized samples were compared with the prototype. After conducting this research and consequently reducing the thickness from 10 to 2.5 mm, a more fine-grained thermomechanical cycle is obtained. The grain size was 37μm in the prototype and 23 and 27μm in the samples for stabilized infrared and resistive furnace, respectively. The hardness of the final sample increased from 75 to 97, compared to the prototype. The corrosion resistance of the stabilized specimen was significantly higher than that of the cold-rolled specimen, with a decrease in mass per unit area of cross section from 58 mg / cm2 to 15 mg / cm2. The yield stress and tensile strength of the stabilized sample increased to 270 MPa and 412 MPa, respectively.
