https://jame.iut.ac.ir/ Journal of Advanced Materials in Engineering en daily 1 Sun, 07 Dec 2025 00:00:00 +0330 Sun, 07 Dec 2025 00:00:00 +0330 https://jame.iut.ac.ir/article_3713.html Introduction and Objectives: Cobalt–chromium–molybdenum (Co–Cr–Mo) alloy, owing to its favorable mechanical properties and biocompatibility, is widely used in medical and aerospace industries. Solution annealing plays a crucial role in improving the microstructure and mechanical properties of this alloy. The aim of this study is to investigate the effect of temperature, holding time, and cooling rate during solution annealing on the microstructure and secondary phases of Co–Cr–Mo alloy. Materials and Methods: Solution annealing was performed at 1125, 1175, and 1225 °C for 1 and 3 hours. After annealing, the samples were cooled in furnace, air, and water environments. The microstructure was examined using optical microscopy, field-emission scanning electron microscopy, and X-ray diffraction analysis. The volume fraction of secondary phases was determined by image analysis. In addition, tensile and microhardness tests were conducted to evaluate the mechanical properties. Results: Increasing the annealing temperature and time enhanced the dissolution of secondary phases and led to a more homogeneous microstructure. Rapid cooling in water significantly reduced the volume fraction of secondary phases from 19.46±1.07% to 1.03±0.02%. In contrast, slow cooling in the furnace resulted in grain growth and re-precipitation of some phases. Mechanical tests revealed that the hardness of the samples reached its minimum value under water and air cooling conditions. Conclusion: Solution annealing at 1225°C for 3 hours, followed by rapid cooling in water or air, had the most pronounced effect on dissolving secondary phases and improving microstructural homogeneity. This condition enhanced the mechanical properties of the Co–Cr–Mo alloy and can be considered as the optimal heat treatment parameters for improving the performance of this alloy. https://jame.iut.ac.ir/article_3736.html Introduction and Objectives: The management of chronic wounds, particularly diabetic foot ulcers, remains a major clinical challenge since infection control, pH regulation, and controlled release of bioactive agents must be achieved simultaneously. In this study, biodegradable composite wound dressings based on chitosan/sodium alginate (Ch/SAG) containing magnesium metal–organic framework (Mg-MOF) and curcumin (Cur) were designed and fabricated. The objectives of this research included: synthesis and characterization of Mg-MOF particles, investigation of the effects of different Mg-MOF concentrations (0, 2, 5, and 10 wt.%) on the physicochemical and morphological properties of the dressings, and evaluation of water absorption, degradation behavior, and curcumin release profiles. The novelty of this work lies in the simultaneous integration of curcumin’s antibacterial and antioxidant functions with the pH-regulating and drug-carrier properties of Mg-MOF within a biocompatible polymeric matrix.Materials and Method: Mg-MOF particles were synthesized via the hydrothermal method. The composite dressings were prepared with a fixed Ch:SAG ratio (80:20), a constant curcumin concentration (0.1 mg/mL), and varying Mg-MOF contents. Structural and morphological features were analyzed using Fourier Transform Infrared Spectrometer, Field Emission Scanining Electron Microscopy, and Energy-Dispersive Spectroscopy. Functional properties—including pH variation, water absorption, degradation, and drug release—were evaluated in Phosphate Buffer Saline.Results: FTIR and FESEM analyses confirmed the composite structure and interactions among the components. Increasing Mg-MOF concentration shifted the pH toward the optimal acidic range (~5) for wound healing. The sample containing 5 wt.% Mg-MOF exhibited the highest water absorption (220 ± 15%, p < 0.01) and a more sustained drug release, whereas the 10 wt.% sample demonstrated greater structural stability.Conclusion: Simultaneous incorporation of Mg-MOF and curcumin significantly improved the physicochemical and functional properties of the Ch/SAG-based dressings, particularly in terms of pH regulation, water absorption, and controlled drug release. The 5 wt.% Mg-MOF concentration was identified as the optimal level for achieving the best performance. https://jame.iut.ac.ir/article_3814.html Introduction and Objectives: Auxetic structures have attracted significant attention in recent years due to their negative Poisson’s ratio and features such as high impact resistance and enhanced energy absorption. Re-entrant structures are among the most widely used auxetic geometries. This study aims to investigate the mechanical behavior and energy absorption capacity of these structures and to propose geometric modifications to improve their performance.Materials and Methods: To determine the mechanical properties of the material, including Young’s modulus and yield stress, standard tensile specimens were fabricated using an FDM 3D printer with PLA+ filament and tested experimentally. A two-dimensional model of the re-entrant structure was then simulated under in-plane quasi-static compression using ABAQUS. To enhance the energy absorption behavior, two geometric modifications were applied, namely replacing sharp re-entrant corners with smooth arc-shaped curves and adding triangular reinforcing members. These modifications were evaluated in both 2D and 3D models.Results: The findings showed that the proposed modifications significantly improved the specific energy absorption without altering the overall deformation mechanism. In the 2D models, improvements of 22% and 44% were observed, while in the 3D models, energy absorption increased by 41% and 66%. Smoother stress distribution and the elimination of sharp angles also delayed structural failure.Conclusion: The results indicate that geometric modifications in re-entrant auxetic structures can effectively enhance their energy absorption performance, offering a practical approach for designing more efficient auxetic systems by combining these modifications. https://jame.iut.ac.ir/article_3835.html Introduction and Objectives: Spinel ferrites are a class of magnetic materials with the general formula AB2O4. These ferrites have attracted the attention of researchers in various fields, especially in medical applications, due to properties such as controllable magnetic behavior. In this regard, magnetic nanoparticles have been used for treatment using magnetic hyperthermia.Materials and Methods: In this study, spinel ferrite nanoparticles Co0.5Zn0.5Fe2O4 were synthesized by two methods: co-precipitation and hydrothermal, using materials such as iron chloride, cobalt chloride, zinc chloride, sodium hydroxide, and ethanol. Their structural, morphological, and magnetic properties were investigated.Results: X-ray diffraction results confirmed the formation of a pure spinel phase in both samples. Field emission scanning electron microscopy images showed that the nanoparticles synthesized by the hydrothermal method had smaller sizes and a more uniform distribution compared to the samples prepared by the co-precipitation method. Fourier transform infrared spectroscopy confirmed the presence of characteristic spinel ferrite bands corresponding to octahedral and tetrahedral sites. Vibrating sample magnetometry results indicated that the sample synthesized by the hydrothermal method possessed a higher saturation magnetization. Consequently, the performance of this sample in magnetic hyperthermia was evaluated.Conclusion: The results indicated that the nanoparticles synthesized by the hydrothermal method demonstrated a desirable ability to release heat, achieving a saturation magnetization of 60.543 emu/g and a specific absorption rate of 20.9 W/g, thus possessing suitable capacity for applications in nanomedicine and magnetic hyperthermia. https://jame.iut.ac.ir/article_3753.html Introduction and Objectives: Betacyclodextrins, as drug carriers, increase the bioavailability of drugs. To enhance the stability of the complex and increase the aqueous solubility of poorly water-soluble drugs, the hydroxyl groups of the betacyclodextrin rings can be modified through chemical alterations. In this study, the interaction between the anticancer drug methotrexate and cyclodextrin, as well as cyclodextrin substituted with mono-chlorotriazinyl, was investigated via docking studies and molecular modeling.Method: To determine the orientation and binding extent of methotrexate to cyclodextrin and to mono-chlorotriazinyl-substituted cyclodextrin, molecular docking calculations were performed using AutoDock 4.2 software. The study examined various positions of mono-chlorotriazinyl substitution on the cyclodextrin structure, and the best docked conformation obtained from the docking results was subjected to molecular dynamics simulations for 500 nanoseconds to assess the stability of the drug-carrier complex.Results: The most favorable binding energy and conformer were for cyclodextrin bearing the mono-chlorotriazinyl substituent at glucose units 1, 2, and 5 (3-mct). Root mean square deviation plots and hydrogen-bond analyses derived from the molecular dynamics simulation of this complex, methotrexate was found to stabilize the complexes, and the complexes exhibited more negative van der Waals interaction energies compared to electrostatic interaction energies. Radius of gyration for the complexed state was slightly lower than for the free state, attributed to water molecules leaving the cavity and the replacement of methotrexate within the mct cavity at a 1:1 ratio. Additionally, the 3-mct substituent increases the accessible surface area for solvent molecules due to its three mono-chlorotriazinyl groups.Conclusion: Based on the docking and molecular dynamics simulations analyses, cyclodextrins bearing the mono-chlorotriazinyl substituent display a greater capability to interact with methotrexate than native cyclodextrin, forming a more stable complex over 500 nanoseconds of simulation. Therefore, this 3-mct substituted betacyclodextrin is recommended for experimental studies. https://jame.iut.ac.ir/article_3815.html Introduction and Objectives: In this study, the effect of electrical current waveform (direct, pulse, and pulse reverse) on the microstructure, chemical composition, crack formation, and corrosion behavior of (Ni-W) alloy coatings obtained by electrodeposition from an additive-free acidic bath was investigated.Materials and Methods: Coatings were deposited on plain carbon steel substrates at a constant current density using direct current, pulse current and pulse reverse current modes. Surface morphology and cross-sectional microstructure were examined by FESEM, crack density was quantified through digital image analysis, chemical composition was determined by EDS, phase structure and lattice parameter were analyzed by XRD, and corrosion behavior was evaluated by potentiodynamic polarization testing in 3.5 wt.% NaCl solution.Results: The direct current coating exhibited the highest tungsten content but also the highest crack density and the highest corrosion current density. The pulsed coatings showed lower crack densities and lower corrosion current densities. In the pulse reverse coating, despite having the lowest tungsten content, no detectable surface cracks were observed in the examined regions and exhibited the lowest corrosion current density. A correlation was observed between crack density and corrosion current density, indicating that structural integrity, is the dominant factor governing the corrosion behavior of these coatings. XRD results confirmed the formation of a single-phase Ni-W solid solution and a markedly higher residual stress in the direct current coating compared to the other coatings.Conclusion: Current waveform engineering, particularly the use of pulse reverse current, is an effective strategy-without the need any stress-reducing chemical additives-for simultaneously achieving a uniform microstructure, a crack-free surface, and corrosion resistance in Ni-W alloy coatings. https://jame.iut.ac.ir/article_3709.html Introduction and Objectives: The widespread application of NiTi alloys in biomedical implants is constrained by the release of nickel ions, which may provoke allergic responses and carcinogenic risks. Employing biocompatible hydroxyapatite composite coatings offers a promising approach to suppress nickel ion leaching and improve the electrochemical performance of NiTi alloys. This study focuses on assessing how varying the concentration of a secondary phase within the composite affects the coating’s composition, microstructure, and the overall electrochemical behavior of the substrate.Materials and Methods: Hydroxyapatite–tantalum oxide composite coatings were produced on NiTi substrates via the electrophoretic deposition method. Tantalum oxide was introduced into the hydroxyapatite nanoparticle suspension at concentrations of 10, 15, and 20 wt.%. All coated samples were sintered at 800 °C for one hour under vacuum conditions.Results: Experimental findings, based on nickel ion release measurements, potentiodynamic polarization, and electrochemical impedance spectroscopy, clearly demonstrate that increasing the content of the secondary phase within the composite significantly enhances the corrosion resistance of the underlying NiTi substrate. The positive effect of the secondary phase on the adhesion strength of hydroxyapatite coating to NiTi was assessed using a tensile test.Conclusion: Engineering composite coatings with dense structural characteristics, designed to restrict the ingress of environmental corrosive species and to block nickel ion diffusion, presents a robust strategy for the safe and durable utilization of NiTi alloys in biomedical applications. https://jame.iut.ac.ir/article_3710.html Introduction and Objectives: Ti-6242 alloy is highly regarded in additive manufacturing due to its excellent thermal resistance. Titanium laser-based additively manufactured components, however, often require post-heat treatments because of their high solidification rate and formation of undesirable phases. The aim of this study is to investigate the effects of annealing heat treatment on the microstructure and mechanical properties of Ti-6242 specimens fabricated by laser powder bed fusion method.Materials and Methods: Annealing heat treatments were conducted at three temperatures of 950, 1005, and 1050 ℃ for holding times of 1, 3, 5, and 7 hours. The resulting microstructure, phase composition, and mechanical properties were characterized using optical and scanning electron microscopy, X-ray diffraction, and shear punch testing.Results: The as-built microstructure consisted of columnar primary β grains with colonies of metastable martensitic α′. Heat treatment led to decomposition of α′ and formation of more stable α and β phases. At 1005 and 1050 °C, the microstructure transformed from columnar to equiaxed, whereas at 950 °C, the columnar structure was retained. Williamson–Hall plots obtained from XRD patterns revealed a reduction in the lattice microstrain of heat treated samples compared with the as-built one. The applied heat treatment, improved both ultimate shear strength and ductility of the samples. The highest ultimate shear strength (761 MPa) and normalized displacement (0.638) were achieved at 1005 °C.Conclusion: Appropriate heat treatment leads to a more stable microstructure, reduction in lattice microstrain, and transformation of the columnar structure to an equiaxed one. This process could simultaneously enhance the ultimate shear strength and ductility compared to the as-built sample. https://jame.iut.ac.ir/article_3799.html Introduction and Objectives: Due to the negative impact of increasing Mg content on the ductility and toughness of Zn-Mg alloys, the use of dilute forms of these alloys has recently become more widespread. In this study, the effect of chill modification and friction stir processing (FSP) on the microstructure and corrosion behavior of dilute Zn-0.3Mg alloy were studied.Materials and Methods: The FSP was performed using a simple cylindrical tool under rotation speed of 1600 rpm and travel speed of 12 mm/min on solidified alloy at a cooling rate of 4.1 °C/s. To investigate the effect of chill modification, the solidification rate was increased from 4.1 to 14.7 °C/s. Tafel polarization and electrochemical impedance spectroscopy (EIS) experiments were performed in simulated body fluid (SBF).Results: The Tafel polarization test results indicated that the corrosion current densities of the chill-modified alloy (20.9 µA/cm2) and friction stir processed alloy (19.6 µA/cm2) are lower than that of the as-cast alloy (38.8 µA/cm2) by about 46 and 49%, respectively. The EIS also implied increasing corrosion resistance of the as-cast alloy from about 50 Ω to 85 Ω and 1.5 kΩ in the chill modified and friction stir processed samples, respectively. Conclusion: Due to the ultrafine and homogenous distribution of Mg2Zn11 particles and development of ultrafine grains (increasing the grain boundary density), the surface of the processed samples (especially the friction stir processed ones) are covered by a continuous and compacted layer composed of corrosion products causing improved corrosion resistance of Zn-0.3Mg alloy. https://jame.iut.ac.ir/article_3800.html Introduction and Objectives: This study redefines the 1400 °C experiment as an over-temperature degradation test rather than a conventional service-temperature oxidation test, and evaluates the microstructural stability limit of conventional and germanium-modified aluminide coatings on Hastelloy X.Materials and Methods: Ge-containing precursor layers were produced by CVD using 600 °C/4 h and 900 °C/2 h routes, followed by CVD aluminizing at 1020 °C for 3 h. The coated specimens were exposed at 1400 °C for 55 h and then characterized by mass-change measurement, cross-sectional BSE observations, semi-quantitative EDS, elemental mapping, and XRD. Results: In the available dataset, ‎Al‎ and Ge900-Al showed net mass changes of -0.09687 and -0.09421 mg/cm², respectively, whereas Ge600-Al retained a positive net mass change of +0.05971 mg/cm². Ge900-Al showed clearer XRD evidence of retained β-NiAl, while Ge600-Al showed the most favorable mass-change response within the present 55 h window. Conclusion: The results should be interpreted as a short-window over-temperature degradation response. The behavior of the coatings is controlled not only by Ge addition but also by the initial coating architecture, the continuity of Ge/Cr-bearing barrier-like regions, and the relative retention of β-NiAl. Because the test temperature exceeds the nominal melting range of Hastelloy X, the results are not intended to represent normal service oxidation behavior. https://jame.iut.ac.ir/article_3801.html Introduction and Objectives: Functionally graded materials are an advanced class of composites which their microstructure change continuously in a specific direction. The main purpose of this paper is to study the microstructure of the Al-13.8 wt.% Mg2Si eutectic alloy produced by centrifugal and gravity casting methods and comparison the effect of addition of Al-5Zr inoculant on the changes in their casting microstructure.Materials and methods: In this research, with gravity and centrifugal casting of Al-13.8wt.% Mg2Si alloy and adding an appropriate amount of Al-5Zr inoculant, microstructural changes in the radial direction of the casting cylinder were compared with gravity casting samples. The chemical composition and microstructural characteristics of the samples were studied using energy-dispersive X-ray spectroscopy and optical microscopy, respectively. Results: The microstructure of the centrifugally cast Al-5Zr inoculant-free cylinder exhibited columnar Al/Mg2Si eutectic cells along the radial direction, accompanied with an accumulation of primary Mg2Si particles in the inner layer of the cylinder. Upon the addition of Al-5Zr inoculant, the morphology of Mg2Si secondary phases changed from cubic to Chinese script shape. However, the microstructure of the conventional gravity casting sample containing and without zirconium showed Al/Mg2Si eutectic cells without a specific targeted distribution, an accumulation of primary and light Mg2Si particles in the upper layer of the casting cylinder, which is due to the separation of these particles against the upward direction of gravity.Conclusion: The microstructure of the cast cylinder processed by centrifugal casting containing Al-5Zr inoculant showed a targeted distribution of Al/Mg2Si eutectic cells and aggregation and reduction in the size of Mg2Si particles in the inner radial layer of the cast cylinder. https://jame.iut.ac.ir/article_3809.html Introduction and Objectives: This study investigates the wear behavior of FeCrCoNiMnTix high-entropy alloy coatings deposited on AISI 431 martensitic stainless steel. Materials and Methods: The alloy powders were prepared via mechanical alloying in a planetary ball mill under an argon atmosphere. To evaluate their wear resistance, the synthesized powders were applied as coatings using the spark plasma sintering technique. Comprehensive analyses, including X-ray diffraction and field emission scanning electron microscopy, revealed that the addition of Ti induces a microstructural transition from a dominant FCC phase to a BCC-rich structure and facilitates the formation of Laves intermetallic phases. Microhardness measurements and pin-on-disk wear test were employed to assess the wear behavior. Results: The results strongly suggest that TiC formed in situ during the SPS process due to the interaction between Ti and carbon. This, combined with solid solution strengthening and the formation of intermetallic phases, resulted in an increase in hardness up to 1030 HV0.05 for the FeCrCoNiMnTi composition. Wear test results indicated that the best performance was achieved by the FeCrCoNiMnTi composition, with a wear rate of approximately 3.78 × 10⁻⁵ mm³/N.m, which is nearly four times lower than that of the AISI 431 stainless steel. Conclusion: This improvement is attributed to the synergistic strengthening effects of the BCC matrix, laves intermetallic phases, and the in-situ formed carbides. The findings of this research suggest that FeCrCoNiMnTi high-entropy alloys are promising candidates for wear-resistant coatings and underscore the critical role of chemical composition design in engineering their structural and tribological properties. https://jame.iut.ac.ir/article_3808.html Introduction and Objectives: Laser drilling is widely used in the aerospace, energy, and medical industries because of its high precision and ability to machine advanced materials. However, the formation of a recast layer, molten material redeposition, and deterioration of hole wall quality remain major challenges in nickel-based superalloys. This study investigated the effects of the processing environment and the application of a magnetic field on the morphological quality of laser-drilled holes in Hastelloy X superalloy using a fiber laser.Materials and Methods: Single-pulse laser drilling experiments were performed on 1-mm-thick Hastelloy X sheets under three processing conditions including argon shielding gas, argon shielding gas with distilled water, and argon shielding gas with distilled water under a magnetic field. The inlet, outlet, sidewall, and longitudinal cross-sectional morphologies of the holes were examined using scanning electron microscopy, while changes in chemical composition were analyzed by energy-dispersive X-ray spectroscopy. Results: The results showed that the processing environment significantly affected molten material behavior, recast layer formation, hole wall quality, and elemental distribution. The use of distilled water reduced molten material redeposition and improved hole wall uniformity. Furthermore, applying a magnetic field guided the molten material flow resulted in fewer surface discontinuities and a more uniform hole wall morphology. energy-dispersive X-ray spectroscopy analysis indicated that compositional changes were mainly confined to the regions adjacent to the hole, whereas the base metal exhibited no significant changes. Conclusion: The results of this research indicated that combined use of distilled water and a magnetic field improved the morphological quality of laser-drilled holes by controlling molten material behavior and reducing its redeposition. This approach can serve as an effective method for enhancing the quality of laser drilling in nickel-based superalloys for engineering applications. https://jame.iut.ac.ir/article_3813.html Introduction and Objectives: Inconel 738 low-carbon (IN738LC) nickel-based superalloy is widely used in high-temperature turbine components due to its high strength and thermal stability. However, microstructural heterogeneity resulting from the solidification process can lead to a non-uniform distribution of strengthening precipitates and deterioration of mechanical performance. The objective of this study was to investigate the effect of increasing the solution heat treatment temperature beyond the standard cycle on the microstructural evolution and mechanical properties of the superalloy.Materials and Methods: Two heat treatment cycles, including a standard cycle and a proposed cycle, were applied to cast specimens. Microstructural changes were evaluated using optical microscopy, scanning electron microscopy, and quantitative image analysis. In addition, hardness and stress rupture tests were conducted to evaluate the mechanical behavior of the alloy.Results: The results showed that increasing the solution temperature significantly reduced microstructural heterogeneity between dendritic core and interdendritic regions. The size of coarse precipitates in interdendritic areas decreased, leading to a more uniform precipitate distribution. Furthermore, the volume fraction of strengthening precipitates increased from 39% to 45%. Carbide investigations indicated that the blocky morphology of MC carbides was preserved, and no evidence of significant decomposition was observed. Hardness increased from 363 HV to 447 HV, while stress rupture life improved from 35 h to 45.8 h.Conclusion: The findings demonstrated that a controlled increase in solution heat treatment temperature can simultaneously improve mechanical properties and high-temperature performance through enhanced microstructural homogenization, increased strengthening precipitate fraction, and preservation of MC carbide stability. These results provide useful insight for designing optimized heat treatment schedules for high-temperature turbine components. https://jame.iut.ac.ir/article_3836.html Introduction and Objectives: Growing demand for biocompatible, efficient materials in cosmetic and textile applications has driven the development of functional hydrogels. This study aimed to prepare a stable hydrogel based on carboxymethyl cellulose and a urea-linked oligomer and evaluate its application in a protective dyeing cap for natural hair-coloring processes.Materials and Methods: hydrogels were prepared in aqueous media using different weight ratios and cured at 70°C for 2 h. A urea-based oligomer was synthesized in the melt state using urea, sulfamic acid, and phosphorous acid at 140°C. The structure and morphology of the hydrogels were characterized using Fourier-transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray analysis, and ion chromatography. The performance of the hydrogel was evaluated within a washable protective cap designed for dyeing wool fibers with henna paste.Results: The prepared hydrogel exhibited a gel fraction of 50% and a swelling capacity of approximately 30 times greater than its initial weight. The results confirmed the formation of a three-dimensional polymer network. The hydrogel was non-toxic and demonstrated favorable antibacterial properties. The use of a hydrogel-containing cap enhanced dye uptake and improved dyeing quality. Color differences among the samples based on a*, b* and L* colorimetric parameters were clearly perceptible after 30 min and evaluated using the International Commission on Illumination system.Conclusion: The developed biocompatible superabsorbent hydrogel demonstrated desirable swelling, antibacterial, and structural properties, making it suitable for cosmetic and personal care applications. Its incorporation into a dyeing cap improved natural dyeing performance by retaining moisture and heat and preventing dye leakage, thereby enhancing dyeing quality.