Journal of Metallurgical and Materials Engineering
Year:2025 | Volume:36 | Issue:2|Papers Count:7

The effect of raw material composition and grinding process by ball mill and HPGR in Golgohar Complex on the properties of the final pellet was investigated. Tests were performed on the mixer input feed in the form of raw material composition analysis, granulation, moisture content and specific surface area measurement using two methods, Blaine and BET. Also, strength measurement and microstructural analysis were performed using SEM on raw and cooked pellets. In addition, the abrasion resistance and sphericity of the pellets were investigated. The results of the tests showed that the particle size produced by the ball mill was finer and had a higher specific surface area (1988 cm2/g). The morphology of the particles produced by the two milling methods was irregular and non-spherical and did not differ significantly from each other. The input feed of the pelletizing plant number one had a higher percentage of FeO, sulfur, and magnesium oxide. Also, microstructural studies of the pellets indicate a better distribution of fine particles and non-magnetic phases in the pellets produced in Plant No. 1. The pellets produced in Plant No. 1 have higher wet strength (WCS), while the dry strength (DCS) and fired strength (CCS) of the pellets produced in Plant No. 2 are higher. In addition, 96.3% of the pellets from the plant number one passed the dumpler abrasion test without crushing, and their sphericity was 0.824, which was higher than that of the pellets produced by the HPGR method.

In the present study, MgFe2O4 spinel synthesized by the combustion method using glycine fuel and red mud obtained from the Jajarm alumina plant were evaluated as two Fe-based catalysts in the esterification process for biodiesel production. To investigate the physico-chemical, and structural characteristics, XRD, FTIR, BET, and FESEM analyses were performed for both samples, and then both samples were used as catalysts in the esterification reaction. The results of the analyses and reactor tests showed that the nano-catalyst synthesized by the combustion method with glycine fuel was very favorable in terms of physical-chemical-structural properties and catalytic performance in the biodiesel production reaction. Under the same reaction conditions, the conversion of the spinel catalyst was 84.6%, while under the same conditions, the conversion rate for red mud was 62.7%. Thus, the red mud and magnesium ferrite spinel (synthesized by the combustion method with glycine fuel) catalysts competed with each other, with the Mg-Fe spinel catalyst performing much more effectively and showing better results compared to the red mud catalyst for the esterification reaction of oleic acid. The results indicated that despite the red mud catalyst being cheaper (a waste product from the aluminum production process), the MgFe2O4 spinel conversion for producing valuable biodiesel fuel was higher. However, it seems that further research is needed for an economic comparison of these two catalysts.

The purpose of this research is to investigate the microstructure and wear behavior of AlA380 alloy nanocomposite reinforced with graphene nanoplates (GNPs) and SiC nanoparticles produced by ball milling and spark plasma sintering furnace (SPS). The percentage of SiC nanoparticles was fixed and the percentage of graphene nanosheets was considered variable. Graphene nanosheets with percentages of 0.25, 0.5, 0.75 and 1% by and SiC nanoparticles at 0.5% by weight were added to the nanocomposite. The presence of dispersed GNPs with high specific surface area significantly increases the strength and hardness of composites. Microstructural studies of the alloy showed that the addition of GNPs up to 0.5 wt% reduced the grain size, but the addition of a higher amount of GNPs (1 wt%) did not significantly change the grain size. At higher GNP values, the presence of graphene agglomerates at the grain boundaries is a favorable path for crack growth. The optimal amount of nanosheets was 0.5% by weight. The wear resistance of the produced nanocomposites is higher than the base sample and the weight reduction of the base sample is 3 times compared to the optimal sample. Due to the self-lubricating nature of graphene, the friction coefficient for the base sample and the nanocomposite containing 0.5% by weight of graphene is 0.689 and 0.455, respectively, which indicates a reduction in the friction coefficient. Also, the hardness of the samples increases from 105 Vickers for the base sample to 175 Vickers for the sample containing 0.5% by weight of graphene.

This study, the effect of adding zirconium diboride (ZrB2) nanoparticles on the microstructure and tensile properties of Al5083 aluminum matrix composite was studied. Al5083-5wt% ZrB2 and Al5083-10wt% ZrB2 nanocomposites were produced by situ-stir casting at 1000°C using in-situ synthesis. Then, the samples were subjected to hot extrusion for uniform distribution of the reinforcements in the matrix. The ZrB2 nanoparticles used in this study were processed in situ using cryolite (Na3AlF6), zirconium oxide (ZrO2) and potassium tetrafluoroboride (KBF4) in molten aluminum. X-ray diffraction (XRD), optical microscopy (OM) and field emission scanning electron microscopy (FE-SEM) were used to investigate the microstructure, surfaces and fracture mechanism of the samples, and tensile testing was used to evaluate the mechanical properties. The tensile test results showed that the addition of 10% by weight of ZrB2 particles, compared to the sample without reinforcement, increased the ultimate tensile strength by 18.2% and reduced the strain by 19.5%. Also, the additional extrusion process reduced the porosity resulting in increased density.

In industry, the polymers are known as efficient corrosion inhibitors. Among them, the natural polymers are of interest with easy access and low price. In the present work, the corrosion inhibition efficiency of agarose was investigated due to the presence of numerous oxygen atoms in the structure, which are capable of protonation in acid. The polarizability and electron density of agarose were enhanced by adding iodide to its structure. Therefore, the corrosion rate of iron samples was investigated in sulfuric acid and the agarose - potassium iodide mixture with different mass ratios (AG, AG:I, AG:2I and AG:3I) as inhibitors. The efficiency of four introduced inhibitors was compared with different techniques such as: Tafel polarization, gravimetry, electrochemical impedance spectroscopy, atomic force microscopy and scanning electron microscopy. Based on the gravimetric results in the presence of 0.5 g/l inhibitor, the percentage of corrosion inhibition increased from 44.14% for AG to 88.68% for AG:3I. Iodine-containing polymer to improve surface Coverage acted as a mixed inhibitor by physically adsorbing on the surface and affecting the anodic and cathodic half-reactions of corrosion. The presence of iodide in the structure of agarose increases the electron density of the inhibitory polymer and strengthens its inhibitory function.

This study investigates the effect of resistance upset butt welding (RUBW) process parameters on the joining of steel bars with different diameters. The conducted evaluations included microstructure, ultimate tensile strength (UTS), elongation, and localized hardness of the welded specimens. Parameter optimization was performed using Central Composite Design (CCD) and Particle Swarm Optimization (PSO) algorithms. The maximum ultimate tensile strength of 628 MPa and an elongation of 25% were achieved under optimal conditions for an 18-mm-diameter rebar, a welding current of 8460 A, and a welding pressure of 1.64 MPa. Analysis of variance showed that the quadratic model provided accurate predictions for ultimate tensile strength, while the linear model was accurate for elongation. The PSO algorithm was used to determine the optimal input parameters, and its results were compared with those from the CCD method. The JMatPro software was used to analyze the phase types and compared with experimental observations. The results showed that the joint interface contained needle-shaped ferrite grains and the heat affected zone exhibited a coarse-grained ferrite-pearlite microstructure.

In the present study, a composite soft robot was constructed using silicon as the matrix and ethanol as the phase change material. the activation mechanism of the silicon-ethanol robot is the absorption of heat by ethanol and the creation of vapor pressure in the silicon matrix and, as a result, strain; therefore, the effect of the uniformity of heat distribution in the composite on its response speed was investigated. The results of this study, using electrical excitation testing, weighing with a balance, imaging of the microstructure by FESEM, and processing of images related to the displacement of the samples by MATLAB software, showed that the heat distribution conditions in composite are very important in the speed and life of the composite. The sample with a coil diameter of 1 cm (equal to 34% of the volume of the sample placed inside the coil to the total volume of the sample) had stable performance during different cycles during operation. The difference in temperature between the center and surface of the sample was approximately 21C, and the average response time over three working days was 161s. For the sample with a coil diameter of 0.8cm, the difference in temperature between the surface and the center was 25C, and the average response time over three working days was 165 seconds. For the sample with a coil diameter of 0.5 cm, the difference in temperature between the surface and the center was 95C, and the average response time over three working days was 143s.