توصيفگر ها :
آلياژ آنتروپي بالا , نورد سرد , آنيل , تبلور مجدد , ريزساختار , خواص مكانيكي , بافت , ساختار دوگانه
چكيده انگليسي :
High entropy alloys have been considered by researchers due to their unique properties. In this study, the behavior of FeNi1.5CrCu0.5 alloy after casting under the process of heat treatment, cold deformation, and recrystallization was studied. In this research, FeNi1.5CrCu0.5 alloy was produced by using vacuum induction melting. The structure and chemical composition have been investigated using X-ray diffraction (XRD) test and Energy dispersive spectroscopy (EDS), microstructure using an optical microscope (OM), and scanning electron microscopy (SEM), and its mechanical properties have been investigated by shear punch and microhardness test. FeNi1.5CrCu0.5 alloy has a single phase with FCC structure and tensile strength is 456 MPa with a 28% increase in length and hardness of 250 Vickers, which indicates the low strength and high flexibility of the alloy in FCC mode. To achieve a-dendritic structure and optimal conditions, Different heat treatment processes on the alloy at temperatures of 900 to 1100 ℃ at a temperature interval of 100 degrees and at different times of 1 and 4 hours were performed, and its effects on the structure of the alloy were fully investigated. Finally, our sample at 1000 ℃ for 15 hours was annealed. FeNi1.5CrCu0.5 alloy was then cold rolling to an 85% reduction in thickness and its structure, mechanical properties, and texture were investigated. It was observed that by performing the rolling process; There was no change in the structure of the XRD compared to the casting stage, and it was the same as the structure of the FCC remained, with the only difference being the intensity of the peaks, indicating the presence of texture in the structure. In the structure of this alloy, with the increase of strain, the share of grain boundaries and misalignments increased, and in the microstructure of shear bands appeared. The strength and hardness of the alloy respectively to 791MPa and 350 Vickers, increased, and also textures with gauss, brass, S, and copper components in the alloy appeared. To obtain the recrystallization temperature, annealing was performed for one hour at different temperatures and the start and end of recrystallization temperatures respectively were 900 and 1050 ℃ and the grain growth temperature was 1100℃. The optimal sample of recrystallization structure was in reducing the different thicknesses of 20, 40, 60, 80, and 90% of the cold rolling, and their microstructure, mechanical properties, and texture were investigated. Samples at different times at 1, 2, 5, 20, 60, 120 min, were annealed. In 1 and 2 min of annealing, there was no change in microstructure and mechanical properties. In 5 min of annealing, recrystallization nucleation took place in areas with high stored energy, in 20 minutes of annealing, the structure completely recrystallized. The main objective of the project is to achieve a bimodal structure, which is a bimodal structure; the result improves strength and flexibility. The bimodal structure was observed at 60 and 120 min of annealing, i.e. in addition to normal grain growth, abnormal grain growth was also observed.
