Papers by kaveh Rahimi Mamaghani
Next research, 2025
The cold sintering process (CSP) has emerged as a groundbreaking alternative to conventional high... more The cold sintering process (CSP) has emerged as a groundbreaking alternative to conventional high-temperature sintering methods, enabling the densification of materials at significantly lower temperatures, typically below 400°C. By utilizing a combination of mechanical pressure, transient liquid phases, and controlled chemical interactions, CSP significantly minimizes energy consumption and preserves the integrity of temperature-sensitive materials, including polymers, nanocomposites, and hybrid systems. This review comprehensively examines the current state of CSP, emphasizing its advantages in energy-efficient manufacturing, material compatibility, and process versatility. Despite its transformative potential, CSP faces several critical challenges, including the need for a deeper understanding of its fundamental mechanisms, process control limitations, scalability constraints, and material-specific densification behaviors. The requirement for post-annealing to remove residual solvents or enhance crystallinity further complicate industrial adoption, as seen in CSP-processed solid-state electrolytes and polymer-ceramic composites. The review explores the role of solvent-mediated mass transport, pressure-assisted diffusion, and interfacial bonding in CSP, highlighting the necessity of advanced characterization techniques and computational modeling for optimizing processing parameters. Furthermore, integrating CSP with emerging technologies such as additive manufacturing, biomedical engineering, energy storage, sustainable manufacturing, and advanced electronics presents promising opportunities for expanding its industrial applications. Future research must focus on improving reproducibility, enhancing process automation, and exploring novel material systems compatible with CSP. Addressing these challenges will unlock the full potential of CSP for sustainable, high-performance material fabrication. This review serves as a comprehensive resource for researchers and industry professionals, outlining key research directions and innovations required to advance CSP from laboratory-scale development to widespread industrial adoption.
Materials Chemistry and Physics, 2025
The cold sintering process (CSP) is a low-temperature densification technique for fabricating hig... more The cold sintering process (CSP) is a low-temperature densification technique for fabricating high-density ceramics, including zinc oxide (ZnO). Optimizing mechanical properties remains challenging due to weak grain boundaries leading to intergranular fracture. This study examines the effects of ZnO particle shapes and organic solvents on densification and tensile strength. ZnO powders with rod-like and isometric morphologies were cold-sintered at 250°C and 530 MPa for 45 minutes using water, dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and N-methyl-2-pyrrolidone (NMP) mixed with 2M acetic acid. Characterization techniques included SEM, BET, XRD, and UV-Vis spectroscopy. The isometric ZnO achieved a higher relative density (97.8%) than rod-like ZnO (96.5%) due to better packing. Among solvents, water yielded the highest density, while DMF resulted in the lowest. Despite polarity significantly impacting densification, solvent viscosity, flashpoint, and pH had negligible effects. Weibull analysis on Brazilian test data estimated the tensile strength of the densest ZnO at 23.9 MPa, with fractography confirming intergranular fracture. Fracture toughness, calculated via the Haberfield and Johnston equation, was 2.5 MPa·m0.5. The addition of MoS2 nanoparticles (up to 1 wt.%) slightly improved tensile strength (<3%), while substituting 2M formic acid for acetic acid led to a 21% enhancement, emphasizing grain boundary reinforcement. These findings highlight the crucial role of solvent chemistry in improving sintering efficiency and mechanical integrity, suggesting future research should focus on optimizing solvent compositions for enhanced performance.
Preparation and properties of bulk ZnO/MoS2 nanocomposite by cold sintering process with three-component solvent
Journal of Materials Science
The cold sintering process was applied as a suitable method to produce high relative density (&am... more The cold sintering process was applied as a suitable method to produce high relative density (&gt; 90%) ZnO/MoS2 nanocomposite. The cold sintering process was done at 170 °C, 480 MPa for 45 min to fabricate ZnO/MoS2 nanocomposite in a bulk form containing 1–5% MoS2. In addition to examining the effective parameters of the process, the proper solvents in cold sintering of ZnO/MoS2 nanocomposite were investigated. The XRD, FTIR, and RAMAN results affirmed the removal of added solvent and the absence of any secondary phase or unknown component in the cold-sintered ZnO/MoS2 nanocomposite. The SEM and EDX results illustrated that to improve the MoS2 nanoparticle homogeneous distribution through the ZnO powders, a new three-component solvent (acetic acid-DMSO-water) with enhanced viscosity should be exerted. Increasing MoS2 nanoparticles resulted in a slight reduction in the final density of the nanocomposite as 5% MoS2 decreased the relative density from 95.2 to 90.9%. The TGA/DTA curves proved that the thermal stability of the fabricated nanocomposite was up to 450 °C. Alongside the bulk form of the produced nanocomposite, UV–visible investigations illustrated that the MoS2 nanoparticles enhanced the ZnO substrate&#39;s visible light absorption, indicating the potential of the cold-sintered ZnO/MoS2 nanocomposite for development in optical applications.
The Mechanical and Tribological Properties of ZnO/MoS 2 Nanocomposite Fabricated by Cold Sintering
The ZnO/MoS2 nanocomposites were fabricated by a cold sintering process using a three-component s... more The ZnO/MoS2 nanocomposites were fabricated by a cold sintering process using a three-component solvent to produce high-density bulks (&gt;90%). The effect of 1-5% MoS2 nanoparticles on mechanical properties (strength, elastic modulus, fracture toughness, and hardness) and tribological properties (mass loss, friction of coefficient, and wear rate) of the material was investigated. The 1% MoS2 improved the hardness and fracture toughness of nanocomposite by 2.22 GPa and 2.33 MPa√m, respectively, with a 23% enhancement in the wear resistance by 1.55×10 −5 mm 3 /N.m. Further increase in the nanoparticle&#39;s value caused a reduction in mechanical properties; however, the nanocomposite&#39;s friction coefficient was proportionally reduced with MoS2 enhancement up to 0.26. The MoS2 nanoparticles, despite the formation of smoother surfaces, have progressed the adhesive mechanism.
Metallurgical and Materials Engineering
The effect of prior constrained groove pressing on friction stir processing (FSP) of pure copper ... more The effect of prior constrained groove pressing on friction stir processing (FSP) of pure copper was investigated. The results illustrate the development of high strain and strength of FSP samples along with an increased strength base metal as a result of applying for a prior constrained groove pressing (CGP) pass. The influences of further FSP passes on the microstructures, and mechanical properties were also shown. The microstructural evaluation of the specimens indicated up to 10 times grain size reduction in FSP specimens as well as equiaxed microstructural morphology. Mechanical properties of the specimens were carried out through tensile and microhardness tests. It was demonstrated that the FSP could improve the strength and ductility of the specimens simultaneously through improved mechanical properties of the base metal resulting from prior CGP. The performed calculations show that values of dislocation density of the CGPed specimens experienced significant change after appl...
Journal of the Taiwan Institute of Chemical Engineers, 2019
Bone is known as the most prevalent, metastatic site of breast cancer; however, it's mechanism de... more Bone is known as the most prevalent, metastatic site of breast cancer; however, it's mechanism details are unknown, so developing a suitable scaffold for bone defect regeneration and sustain drug release after tumor resection can considerably inhibit the tumor recurrence after a while. Here, synthesized gelatin/beta-tricalcium phosphate (β-TCP) nanocomposite scaffold loaded with zoledronic acid (ZA) drug with different β-TCP concentrations, crosslinker and varying drug doses were investigated to highlight their effect on biological properties of the scaffold cont ained bone cells. The scanning electron microscopy (SEM) illustrated porous structure (50-200 μm) of gelatin reinforced with β-TCP spherical nanoparticles (around 90 nm diameter) that could be a proper matrix for bone cells proliferation. In vitro biological analysis by cytotoxicity assay (MTT test) as well as osteoblast cell line (G292) attachment test showed that the scaffolds were biocompatible and non-toxic. Also, higher β-TCP nanoparticle concentration enhanced the rate of cell proliferation on the scaffold. Further investigations indicated that the type of cell seeding into porous scaffolds should be considered as a significant parameter in cell behavior on the scaffold. The better cell attachment was observed in agarose gel wells in comparison with the petri dish one. Nanocomposite samples were loaded with ZA drug and its effects on the cell proliferation were investigated in vitro and in vivo as well. Histopathological results showed that the new bone formation was established more than 75% in the whole area of the defect after 3 and 4 months. For the first time, nanoscaled β-TCP/gelatin composite was proposed as a potential for controlled drug release and local resected tumor treatment. All findings besides in vitro and in vivo analyses, recommend gelatin/nano beta-tricalcium phosphate/drug scaffolds as a promising three-dimensional environment for repairing the resected bone tissue in primary or metastatic bone sites.
Materials Today: Proceedings, 2018
In this research, H-NMR utilized to characterize gelatin methacrylate (GelMa) and polyethylene gl... more In this research, H-NMR utilized to characterize gelatin methacrylate (GelMa) and polyethylene glycol diacrylate (PEGDA), indicating that GelMa with 94% degrees of substitution (DS) and PEGDA with almost 90% degree of acrylation (DA) were successfully synthesized. The XRD calculations estimated the layer distance of graphene oxide (GO) to be about 0.8 nm. The ratio of D/G peaks in Raman outputs of GO was 1.1 and the presence of some peaks in the 2D region demonstrated that it had few layers. The elastic modulus variations illustrated that higher GelMa concentration could enhance mechanical properties of hydrogel significantly. Moreover, higher ratio of PEGDA in the interpenetrating network (IPN) hydrogels strengthened it considerably. The presence of GO into the hydrogels improved its mechanical properties. In all specimens, swelling ratio and mechanical properties were inversely related to adding PEGDA or GO in the hydrogels decreasing their swelling ratio. Therefore, in the GelMA/PEGDA/GO hydrogel, the mechanical and swelling behavior could be engineered by different ratios of polymers and GO. These results could introduce IPN hydrogels containing nanomaterials for further progress in biomedical applications.
Micro & Nano Letters, 2018
Graphene oxide (GO) was successfully synthesised via modified Hummer method and functionalised by... more Graphene oxide (GO) was successfully synthesised via modified Hummer method and functionalised by methacrylate named MeGO (metacrylated GO). Different characterisation methods containing UV-vis, Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, field emission scanning electron microscope (FESEM), transmission electron microscope (TEM) and atomic force microscope (AFM) analyses were employed to characterise the structure and morphology of MeGO. The outputs of the different analyses confirmed each other and proved the presence of the methacrylate functional group on the surface of the GO. Displacement in the peaks of UV-vis analysis coupled with the new peaks in FTIR results clearly demonstrated the creation of a new functional group. The G/D ratio of MeGO in Raman spectroscopy has increased to 1.17 and FESEM and TEM investigations confirmed the wrinkled structure of MeGO sheets. Also, it was observed that the distance between the GO layers was increased about 2.86 nm after functionalisation of GO layers by methacrylate groups. This nanomaterial with difference characterisation and specific properties in comparison with GO could be a great candidate for further developments in industrial and biomedical applications.
International Journal of Electrochemical Science, 2017
Nanocrystalline pure nickel coating was electroplated on pure copper by means of a modified Watts... more Nanocrystalline pure nickel coating was electroplated on pure copper by means of a modified Watts bath with variant stirring rates and current densities. The crystallite sizes were calculated by XRD analysis. The crystallite size had an inverse relation with stirring rate and current density in the plating bath. The best corrosion resistance was observed in 5 A/dm 2 current density of polarization test and corrosion rate smoothly increased by agitation in the plating bath. The microstructure evolution at high stirring rates exhibited some surface bubbles that affected the surface quality and properties. Although Vickers microhardness increased by the addition of the current density, our measurements showed that the hardness had an inverse relationship with turbulence in the solution. An optimum agitation in the bath could improve the hardness distribution on the coated specimen. However, specimens with agitation did not follow the Hall-Petch relationship between crystallite size and microhardness.
The Effect of Direct and Cross-Rolling on Mechanical Properties and Microstructure of Severely Deformed Aluminum
Journal of Materials Engineering and Performance, 2013
Severely deformed commercial pure aluminum sheets by constrained groove pressing are direct and c... more Severely deformed commercial pure aluminum sheets by constrained groove pressing are direct and cross-rolled. The grain size evolution and dislocation density during rolling are studied using Williamson-Hall analysis on x-ray diffraction patterns of the deformed samples. These results and optical microscopy observations show that subsequent direct or cross-rolling of constrained groove pressed aluminum can produce elongated fine grains. The minimum crystallite size is achieved after cross rolling of constrained groove pressed samples. By direct rolling or cross-rolling of annealed sheet, the maximum intensity in x-ray diffraction patterns remains on (200) like annealed aluminum but direct rolling or cross-rolling of constrained groove pressed sheets changes the maximum intensity from (111) for constrained groove pressed sheets to (220). Also, mechanical properties are studied using tensile test and hardness measurement. The results show that cross rolling on constrained groove pressed samples is more effective than direct rolling in mechanical properties improvement.
Neural Network World, 2013
In the present study, bainite fraction results of continuous cooling of high strength low alloy s... more In the present study, bainite fraction results of continuous cooling of high strength low alloy steels have been modeled by artificial neural networks. The artificial neural network models were constructed by 16 input parameters including chemical compositions (C, Mn, Nb, Mo, Ti, N, Cu, P, S, Si, Al, V), Nb in solution, austenitizing temperature, initial austenite grain size and cooling rate over the temperature range of the occurrence of phase transformations. The value for the output layer was the bainite fraction. According to the input parameters in feed-forward back-propagation algorithm, the constructed networks were trained, validated and tested. To make a decision on the completion of the training processes, two termination states are declared: state 1 (ANN-I model) means that the training of neural network was ended when the maximum epoch of process reached (1000) while state 2 (ANN-II model) means the training ended when minimum error norm of network gained. The entire statistical evaluators of ANN-II model has higher performance than those of ANN-I. However, both of the models exhibit valuable results and the entire statistical values show that the proposed ANN-I and ANN-II models are suitably trained and can predict the bainite fraction values very close to the experimental ones.
Journal of Materials Science, 2023
The cold sintering process was applied as a suitable method to produce high relative density (> 9... more The cold sintering process was applied as a suitable method to produce high relative density (> 90%) ZnO/MoS2 nanocomposite. The cold sintering process was done at 170 °C, 480 MPa for 45 min to fabricate ZnO/MoS2 nanocomposite in a bulk form containing 1–5% MoS2. In addition to examining the effective parameters of the process, the proper solvents in cold sintering of ZnO/MoS2 nanocomposite were investigated. The XRD, FTIR, and RAMAN results affirmed the removal of added solvent and the absence of any secondary phase or unknown component in the cold-sintered ZnO/MoS2 nanocomposite. The SEM and EDX results illustrated that to improve the MoS2 nanoparticle homogeneous distribution through the ZnO powders, a new three-component solvent (acetic acid-DMSO-water) with enhanced viscosity should be exerted. Increasing MoS2 nanoparticles resulted in a slight reduction in the final density of the nanocomposite as 5% MoS2 decreased the relative density from 95.2 to 90.9%. The TGA/DTA curves proved that the thermal stability of the fabricated nanocomposite was up to 450 °C. Alongside the bulk form of the produced nanocomposite, UV–visible investigations illustrated that the MoS2 nanoparticles enhanced the ZnO substrate's visible light absorption, indicating the potential of the cold-sintered ZnO/MoS2 nanocomposite for development in optical applications.
Materialia, Elsevier, Jul 4, 2023
The ZnO/MoS2 nanocomposites were fabricated by a cold sintering process using a three-component s... more The ZnO/MoS2 nanocomposites were fabricated by a cold sintering process using a three-component solvent to produce high-density bulks (>90%). The effect of 1-5% MoS2 nanoparticles on mechanical properties (strength, elastic modulus, fracture toughness, and hardness) and tribological properties (mass loss, friction of coefficient, and wear rate) of the material was investigated. The 1% MoS2 improved the hardness and fracture toughness of nanocomposite by 2.22 GPa and 2.33 MPa√m, respectively, with a 23% enhancement in the wear resistance by 1.55×10 −5 mm 3 /N.m. Further increase in the nanoparticle's value caused a reduction in mechanical properties; however, the nanocomposite's friction coefficient was proportionally reduced with MoS2 enhancement up to 0.26. The MoS2 nanoparticles, despite the formation of smoother surfaces, have progressed the adhesive mechanism.
Materials Today: Proceedings, 2018
In this research, gelatin methacrylate (GelMa), polyethylene glycol diacrylate (PEGDA) and graphe... more In this research, gelatin methacrylate (GelMa), polyethylene glycol diacrylate (PEGDA) and graphene oxide (GO) were characterized by UV-Vis and FTIR. The UV-Vis output beside the new peaks in the FTIR analysis approved the synthesized materials. The SEM observations indicated that the GelMa concentration had a reverse relationship with the hydrogel pore size and its distribution. Moreover, in GelMa/PEGDA hybrid, a higher ratio of PEGDA refined the hydrogel microstructure considerably. The addition of 5wt% PEGDA to the 5wt% GelMa reduced the pore size from 44μm to 25μm. The pore size of the GelMA/PEGDA hybrid with 10wt% could be adjusted in the range of 5μm to 50μm. Also, the AFM results of GO estimated its layer number about 10 which had been dispersed into the hybrid hydrogel successfully. Therefore, in the GelMA/PEGDA/GO hydrogel, the microstructure could be engineered by different ratios of polymers also the addition of GO could be useful in modifying specific properties. These findings could introduce hybrid hydrogel containing nanomaterials in further advances for biomedical purposes.
Materials Today: Proceedings, 2018
In this research, H-NMR utilized to characterize gelatin methacrylate (GelMa) and polyethylene gl... more In this research, H-NMR utilized to characterize gelatin methacrylate (GelMa) and polyethylene glycol diacrylate (PEGDA), indicating that GelMa with 94% degrees of substitution (DS) and PEGDA with almost 90% degree of acrylation (DA) were successfully synthesized. The XRD calculations estimated the layer distance of graphene oxide (GO) to be about 0.8 nm. The ratio of D/G peaks in Raman outputs of GO was 1.1 and the presence of some peaks in the 2D region demonstrated that it had few layers. The elastic modulus variations illustrated that higher GelMa concentration could enhance mechanical properties of hydrogel significantly. Moreover, higher ratio of PEGDA in the interpenetrating network (IPN) hydrogels strengthened it considerably. The presence of GO into the hydrogels improved its mechanical properties. In all specimens, swelling ratio and mechanical properties were inversely related to adding PEGDA or GO in the hydrogels decreasing their swelling ratio. Therefore, in the GelMA/PEGDA/GO hydrogel, the mechanical and swelling behavior could be engineered by different ratios of polymers and GO. These results could introduce IPN hydrogels containing nanomaterials for further progress in biomedical applications.
Nanocrystalline pure nickel coating was electroplated on pure copper by means of a modified Watts... more Nanocrystalline pure nickel coating was electroplated on pure copper by means of a modified Watts bath with variant stirring rates and current densities. The crystallite sizes were calculated by XRD analysis. The crystallite size had an inverse relation with stirring rate and current density in the plating bath. The best corrosion resistance was observed in 5 A/dm 2 current density of polarization test and corrosion rate smoothly increased by agitation in the plating bath. The microstructure evolution at high stirring rates exhibited some surface bubbles that affected the surface quality and properties. Although Vickers microhardness increased by the addition of the current density, our measurements showed that the hardness had an inverse relationship with turbulence in the solution. An optimum agitation in the bath could improve the hardness distribution on the coated specimen. However, specimens with agitation did not follow the Hall–Petch relationship between crystallite size and microhardness.
In the present study, bainite fraction results of continuous cooling of high strength low alloy s... more In the present study, bainite fraction results of continuous cooling of high strength low alloy steels have been modeled by artificial neural networks. The artificial neural network models were constructed by 16 input parameters including chemical compositions (C, Mn, Nb, Mo, Ti, N, Cu, P, S, Si, Al, V), Nb in solution , austenitizing temperature, initial austenite grain size and cooling rate over the temperature range of the occurrence of phase transformations. The value for the output layer was the bainite fraction. According to the input parameters in feed-forward back-propagation algorithm, the constructed networks were trained, validated and tested. To make a decision on the completion of the training processes , two termination states are declared: state 1 (ANN-I model) means that the training of neural network was ended when the maximum epoch of process reached (1000) while state 2 (ANN-II model) means the training ended when minimum error norm of network gained. The entire statistical evaluators of ANN-II model has higher performance than those of ANN-I. However, both of the models exhibit valuable results and the entire statistical values show that the proposed ANN-I and ANN-II models are suitably trained and can predict the bainite fraction values very close to the experimental ones.
Severely deformed commercial pure aluminum sheets by constrained groove pressing are direct and c... more Severely deformed commercial pure aluminum sheets by constrained groove pressing are direct and cross-rolled. The grain size evolution and dislocation density during rolling are studied using Williamson-Hall analysis on x-ray diffraction patterns of the deformed samples. These results and optical microscopy observations show that subsequent direct or cross-rolling of constrained groove pressed aluminum can produce elongated fine grains. The minimum crystallite size is achieved after cross-rolling of constrained groove pressed samples. By direct-rolling or cross-rolling of annealed sheet, the maximum intensity in x-ray diffraction patterns remains on (200) like annealed aluminum but direct-rolling or cross-rolling of constrained groove pressed sheets changes the maximum intensity from (111) for constrained groove pressed sheets to (220). Also, mechanical properties are studied using tensile test and hardness measurement. The results show that cross-rolling on constrained groove pressed samples is more effective than direct-rolling in mechanical properties improvement.
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Papers by kaveh Rahimi Mamaghani