Effect of sintering parameters on the microstructure and compressive mechanical properties of porous Fe scaffold fabricated using 3D printing and pressure less microwave sintering

Abstract

The demand for the porous scaffold has been increasing globally in the biomedical field due to numerous advantages over dense structures like high damping capacity, high specific strength, and improved cell integration growth. In the present study, porous iron scaffolds were fabricated using micro-extrusion-based three-dimensional printing and pressureless microwave sintering. For the preparation of samples, metal-based polymeric ink was developed. Thereafter, cylindrical samples were printed and then sintered in a microwave sintering furnace. The experimental investigations were performed to estimate the effect of sintering parameters such as sintering temperature, heating rate and soaking time on the compressive and microstructural property of the fabricated samples. Microstructural characterization was done using the electron backscatter diffraction technique. The experimental observations deduced that the compressive yield strength and apparent density of the sintered sample increased with the increase in sintering temperature and decreased with a further rise in temperature. Moreover, the electron backscatter diffraction analysis unveiled that the high heating rate resulted in the reduction of compressive yield strength due to rapid grain growth. Additionally, the significant effect of soaking time on the compressive mechanical properties was also noticed due to the increase in the grain size diameter. From the X-ray diffraction plot, it was found that there was no contamination present in the fabricated scaffold. In order to evaluate the process capability, a case study was performed wherein the topologically ordered porous structure of iron was fabricated at optimum sintering parameters.

Corrosion behavior and degradation mechanism of micro‐extruded 3D printed ordered pore topological Fe scaffolds

“…These variations were observed as the resulted effect of shrinkage in the fabricated OPTFS. The deviation in dimensions of the prepared Fe scaffold as compared to the CAD model was obtained in the range of 27 The reasons could be attributed to the shrinkage in prepared H‐OPTFS due to the diffusions and misorientations of CIPs during pressureless microwave sintering 26 . Initially, metal particles (CIPs) were slackly bonded with a polymer in micro‐extruded 3D printed part because no compaction was applied prior to heating 26 .…”

“…The metal‐based polymeric ink was made ready by utilizing the right proportion of solvent mixture: dichloromethane (DCM), 2‐butoxyethanol, and dibutyl phthalate (supplier, Thermo‐fisher). The route followed for preparing the metal‐based polymeric ink was the same as described in the reported studies 25,26 . Further to this, green bodies of the desired CAD model was printed using prepared metal‐based polymeric ink with the aid of a micro‐extrusion‐based 3D printer (Biobot) 27,28 .…”

“…The optimum process parameters were adopted in the present study for fabricating the green body was calculated based on central composite design and Genetic Algorithm, respectively 25 . In addition to this, pressureless microwave sintering of printed green bodies was heated in a microwave sintering furnace (Frequency: 2.45 GHz and Power: 1.45 kW; supplier: Enerzi microwave, India) within the zero‐grade argon gas atmosphere 26,27 …”

“…The cylinder‐shaped Fe samples of dimensions Ø 10 ⨯ 15 which have inherent characteristics of TFPM were fabricated by developed manufacturing techniques 26,27 . The sintering cycle used for fabricating the TFPM cylindrical shaped samples have been presented in Figure 1A 26 . The formation of random porous Fe scaffolds (RPFS) which have TFPM characteristics was designated as T‐1 specimen.…”

“…Further, the two‐stage sintering cycle used for fabricating the H‐OPTFS and the same has been illustrated from Figure 1A. The sintering parameters used for fabricating the H‐OPTFS in the present study were adopted from the investigations performed by Mishra and Pandey 26 . The developed metal scaffolds were further cleaned using sandblasting technique with a range of 75 μm size of glass bead.…”