https://www.foundingjournal.ir/ Founding Research Journal en daily 1 Sun, 01 Jun 2025 00:00:00 +0330 Sun, 01 Jun 2025 00:00:00 +0330 https://www.foundingjournal.ir/article_222186.html The aim of the present research is to investigate the hot workability behavior of AISI 303Se stainless steel in both cast and worked conditions. To this end, the AISI 303Se stainless steel was produced using an induction furnace and subjected to homogenization, dissolution, and annealing heat treatments within the temperature range of 1000 to 1200 °C. Samples of both cast and worked steel were cut for tensile testing at temperatures ranging from 900 to 1200 °C. Optical microscopy and tensile testing were employed to examine the microstructure and mechanical properties, respectively. The results of the microscopic tests indicated that heat treatment and hot rolling reduced the average grain size of the steel from 70 µm to approximately 25 µm. The heat treatment and rolling led to a reduction in the high-temperature strength of AISI 303Se stainless steel by about 38%. However, the implementation of heat treatment and hot rolling increased the ductility of the AISI 303Se stainless steel by approximately 36%. The Desiarble temperature for hot working of cast AISI 303Se stainless steel was found to be 1100 °C, while for worked AISI 303Se stainless steel, it was in the range of 1050-1100 °C. In both types of steel, whether cast or worked, complete recrystallization occurred at 1050 °C; however, recrystallization in the worked steel resulted in a finer-grained structure and consequently a wider hot working window. https://www.foundingjournal.ir/article_222188.html The aim of the present study is to investigate the occurrence of the α2 to α phase transformation during hot compressive deformation of Ti-48Al-2Cr-2Nb intermetallic. To this end, hot compression tests were performed on samples of the intermetallic at temperatures of 1000, 1050, 1100, and 1150°C, with a constant strain rate of 0.01 s⁻¹. After hot deformation at 1000 and 1050°C, tall peaks of the γ phase, along with relatively shorter peaks of the α2 phase, were observed in the X-ray diffraction analysis results. With the increase in deformation temperature to 1100 and 1150°C, the α2 phase peaks disappeared, and peaks of the α phase emerged. After hot deformation at 1000 and 1050°C, bent and broken lamellae, along with some recrystallized grains, were observed in the microstructure. However, with the increase in hot deformation temperature to 1100°C, the onset of transformation led to the decomposition of the α2 phase, creating decomposed regions rich in the γ phase, thus increasing the amount of this phase in the microstructure. Therefore, based on the above results, it can be concluded that the ordering transformation begins in the temperature range of 1050 to 1100°C and completes in the range of 1100 to 1150°C. https://www.foundingjournal.ir/article_234149.html In this study, the laser cladding of high entropy alloy TiNiCrMoW-ZrB2 coating on Inconel 738 (IN738) superalloy was numerically simulated using Sysweld software. The aim was to accurately predict the temperature field, temperature gradients, molten pool dimensions, and investigate the effect of process parameters such as laser power, scanning speed, and powder feed rate on the microstructure and final quality of the coating. The 3D finite element model designed by considering conductive, convective, and radiative heat transfer was able to reproduce the thermal behavior of the process with high accuracy. In numerical modeling, a Gaussian heat source with an elliptical power distribution was used to accurately represent the laser beam, and boundary conditions including conduction in the substrate, surface convection, and thermal radiation to the environment were applied to reproduce the real heat transfer behavior in the simulation process. The simulation results showed that increasing the laser power and decreasing the scanning speed led to an increase in the molten pool temperature, improved melting, and metallurgical bonding to the substrate. Comparison of numerical data with experimental results obtained from thermocouple measurements showed very good agreement, which confirms the accuracy of the model. Overall, the use of thermal simulation is an effective method to optimize process parameters, reduce costs, and gain a deeper understanding of the thermal and microstructural behavior of high-entropy alloys in laser cladding. https://www.foundingjournal.ir/article_235108.html In this paper, the microstructural characteristics of the interface in a bimetallic aluminum composite with a regular 3D lattice copper preform produced by squeeze casting are numerically analyzed. To this end, the effects of three variables—the wall thickness of the lattice copper preform, the pouring temperature of the aluminum melt, and the squeeze pressure—on the interface thickness, eutectic cell thickness, and θ-phase thickness were investigated. An L15 orthogonal array was used for the experimental design, with all three independent variables set at three levels with equal spacing. Numerical regression analysis, analysis of variance (ANOVA), and main and interaction effect functions using surface plots were employed to demonstrate the effects of the variables. The interface microstructure was examined using optical and electron microscopes equipped with image analysis and EDS. The results indicate that the interfacial microstructure of the composite consists of four layers: pure copper, the θ phase, the α+θ eutectic, and the aluminum α phase. The preform thickness is the most influential factor affecting the thickness and morphology of the intermetallic compounds at the interface, followed by the pouring temperature and squeeze pressure. For the preform thickness parameter, the highest and lowest data points for both the eutectic cell thickness and θ-phase thickness responses were obtained at the 0.75 mm and 1.25 mm levels, respectively. As the preform thickness increased from 0.75 mm to 1.25 mm, the average data for the eutectic cell thickness response decreased by 45.2% and for the θ-phase thickness by 58.3%. https://www.foundingjournal.ir/article_235109.html In this research, to investigate the effect of metallurgical parameters such as pouring temperature, equivalent carbon and feeding conditions on the metallurgical quality of ductile iron parts (absence of shrinkage hole and cold shut defects), a bell-shaped piece used in the suspension system of automobile parts was used. For this purpose, equivalent carbon from 4.3 to 4.5 wt%, pouring temperature from 1380 to 1440°C and feeding in three conditions of no feeding, closed feeding and open feeding were investigated. In order to reduce the number of experiments, the Taguchi method was used to design the experiments. The results of the experiments showed that equivalent carbon of nearly 4.3 wt%, high pouring temperature for cold shut and low pouring temperature for shrinkage hole defects and the use of open feeding conditions provided the most suitable conditions so that none of the shrinkage hole and cold shut defects were observed under these conditions. https://www.foundingjournal.ir/article_239909.html During producing bimetallic aluminum alloys by centrifugal casting, the presence of aluminium oxide film on the solid surface prevents the achievement of suitable metallurgical bond between two layers . In this study aims to investigate the effect of the second-layer casting conditions were investigated on the properties of the bimetallic joint between the strontium-modified aluminum alloy A356 (first layer) and the Al-15Sn-4Si-1Mg alloy (second layer) using the centrifugal casting method. The temperature of the inner surface of the first layer (566, 530, and 500 °C) and the ratio of the second-layer thickness to the first-layer thickness (0.1, 0.2, and 0.3) were selected as process variables. The microstructure and strength properties of produced samples were evaluated to characterize the interface between the two layers. Microstructural observations showed that due to the presence of magnesium and tin elements in the second layer alloy along with centrifugal force, the aluminium oxide layer on the solid surface of A356 was subjected to reduction and rupture. Based on the results of the joint shear strength test, the sample cast at the first layer inner surface temperature of 530 °C and the ratio of 0.2 showed the highest shear strength of 99.40 MPa, and the sample with the first layer inner surface temperature of 500 °C and the ratio of 0.1 showed the lowest shear strength of 41.48 MPa at the joint. https://www.foundingjournal.ir/article_238780.html Accurate determination of the beta transus temperature is essential for the appropriate design of thermomechanical and heat treatment processes, which directly influence the mechanical performance of titanium alloys. In the present work, the beta transus temperature of a near-alpha titanium alloy, Ti-811, was identified through detailed microstructural investigations. Samples were solution-treated at 1000, 1020, 1040, 1050, and 1060 °C for 1 h, followed by water quenching. Microstructural characterization was performed using optical microscopy and scanning electron microscopy. Metallographic analyses, aimed at determining the onset temperature of grain boundary alpha precipitation and tracking microstructural evolution during phase transformation, revealed the presence of secondary alpha and grain boundary alpha phases between 1000 and 1050 °C, consistent with the alloy’s dual-phase characteristics. In contrast, no secondary or grain boundary alpha phases were detected at 1060 °C, where the microstructure was fully composed of beta grains. Based on these observations, the beta transus temperature of Ti-811 alloy investigated in this study was determined to lie within the range of 1050–1060 °C.