This study investigated the densification behavior of rhenium alloys including W-25 wt.%Re and Re-2W- 1Ta (pure Re) during sintering. The dilatometry experiments were carried out to obtain the in-situ shrinkage in H₂ atmosphere. The measured data was analyzed through shrinkage, strain rate and relative density, and then symmetrically treated to construct the linearized form of master sintering curve (MSC) and MSC as a well-known and straightforward approach to describe the densification behavior during sintering. The densification behaviors for each material were analyzed in many respects including apparent activation energy, densification parameter, and densification ratio. MSC with a minimal set of preliminary experiments can make the densification behavior to be characterized and predicted as well as provide guideline to sinter cycle design. Considering the results of linearized form and MSC, it was confirmed that the W-25 wt.%Re compared to Pure Re is more easily densified at the relatively low temperature.

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• The influence of sintering time on the microstructural properties of chromium-rhenium matrix composites
  Marcin Chmielewski, Szymon Nosewicz, Dorota Jakubowska, Małgorzata Lewandowska, Jarosław Mizera, Jerzy Rojek, Piotr Bazarnik
  International Journal of Refractory Metals and Hard Materials.2016; 59: 78.     CrossRef

High-entropy alloys (HEAs) are attracting attention because of their excellent properties and functions; however, they are relatively expensive compared with commercial alloys. Therefore, various efforts have been made to reduce the cost of raw materials. In this study, MIM is attempted using coarse equiatomic CoCrFeMnNi HEA powders. The mixing ratio (powder:binder) for HEA feedstock preparation is explored using torque rheometer. The block-shaped green parts are fabricated through a metal injection molding process using feedstock. The thermal debinding conditions are explored by thermogravimetric analysis, and solvent and thermal debinding are performed. It is densified under various sintering conditions considering the melting point of the HEA. The final product, which contains a small amount of non-FCC phase, is manufactured at a sintering temperature of 1250°C.

Nanopowders provide better details for micro features and surface finish in powder injection molding processes. However, the small size of such powders induces processing challenges, such as low solid loading, high feedstock viscosity, difficulty in debinding, and distinctive sintering behavior. Therefore, the optimization of process conditions for nanopowder injection molding is essential, and it should be carefully performed. In this study, the powder injection molding process for Fe nanopowder has been optimized. The feedstock has been formulated using commercially available Fe nanopowder and a wax-based binder system. The optimal solid loading has been determined from the critical solid loading, measured by a torque rheometer. The homogeneously mixed feedstock is injected as a cylindrical green body, and solvent and thermal debinding conditions are determined by observing the weight change of the sample. The influence of the sintering temperature and holding time on the density has also been investigated. Thereafter, the Vickers hardness and grain size of the sintered samples have been measured to optimize the sintering conditions.

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• Investigation of stainless steel 316L/zirconia joint part fabricated by powder injection molding
  Chang Woo Gal, Sang Soo Han, Jun Sae Han, Dongguo Lin, Seong Jin Park
  International Journal of Applied Ceramic Technology.2019; 16(1): 315.     CrossRef
• Fabrication and properties of Si3N4 based ceramics using combustion synthesized powders
  Chang Woo Gal, Gi Woung Song, Woon Hyung Baek, Hyung Kyu Kim, Dae Keun Lee, Ki Wook Lim, Seong Jin Park
  International Journal of Refractory Metals and Hard Materials.2019; 81: 325.     CrossRef
• Powder Injection Molding Process in Industrial Fields
  Joo Won OH, Chang Woo GAL, Daseul SHIN, Jae Man PARK, Woo Seok YANG, Seong Jin PARK
  Journal of the Japan Society of Powder and Powder Metallurgy.2018; 65(9): 539.     CrossRef

In this study, a finite element analysis approach is proposed to predict the fluid-structure interaction behavior of active materials for lithium-ion batteries (LIBs), which are mainly composed of graphite powder. The porous matrix of graphite powder saturated with fluid electrolyte is considered a representative volume element (RVE) model. Three different RVE models are proposed to consider the uncertainty of the powder shape and the porosity. Pwave modulus from RVE solutions are analyzed based on the microstructure and the interaction between the fluid and the graphite powder matrix. From the results, it is found that the large surface area of the active material results in low mechanical properties of LIB, which leads to poor structural durability when subjected to dynamic loads. The results obtained in this study provide useful information for predicting the mechanical safety of a battery pack.

A powder injection molding process is developed and optimized for piezoelectric PAN-PZT ceramics. Torque rheometer experiments are conducted to determine the optimal solids loading, and the rheological property of the feedstock is evaluated using a capillary rheometer. Appropriate debinding conditions are chosen using a thermal gravity analyzer, and the debound specimens are sintered using sintering conditions determined in a preliminary investigation. Piezoelectric performance measures, including the piezoelectric charge constant and dielectric constant, are measured to verify the developed process. The average values of the measured piezoelectric charge constant and dielectric constant are 455 pC/N and 1904, respectively. Powder injection molded piezoelectric ceramics produced by the optimized process show adequate piezoelectric performance compared to press-sintered piezoelectric ceramics.

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• Study on Rheological Behavior and Mechanical Properties of PMN–PZT Ceramic Feedstock
  Jae Man Park, Jun Sae Han, Joo Won Oh, Seong Jin Park
  Metals and Materials International.2021; 27(5): 1069.     CrossRef
• Investigation of stainless steel 316L/zirconia joint part fabricated by powder injection molding
  Chang Woo Gal, Sang Soo Han, Jun Sae Han, Dongguo Lin, Seong Jin Park
  International Journal of Applied Ceramic Technology.2019; 16(1): 315.     CrossRef
• Fabrication of pressureless sintered Si3N4 ceramic balls by powder injection molding
  Chang Woo Gal, Gi Woung Song, Woon Hyung Baek, Hyung Kyu Kim, Dae Keun Lee, Ki Wook Lim, Seong Jin Park
  Ceramics International.2019; 45(5): 6418.     CrossRef
• Experimental analysis for fabrication of high-aspect-ratio piezoelectric ceramic structure by micro-powder injection molding process
  Jun Sae Han, Chang Woo Gal, Jae Man Park, Jong Hyun Kim, Seong Jin Park
  Materials Research Express.2018; 5(4): 046303.     CrossRef

Powder injection molding (PIM), which combines the advantages of powder metallurgy and plastic injection molding technologies, has become one of the most efficient methods for the net-shape production of both metal and ceramic components. In this work, plasma display panel glass bodies are prepared by the PIM process. After sintering, the hot isostatic pressing (HIP) process is adopted for improving the density and mechanical properties of the PIMed glass bodies. The mechanical and thermal behaviors of the prepared specimens are analyzed through bending tests and dilatometric analysis, respectively. After HIPing, the flexural strength of the prepared glass body reaches up to 92.17 MPa, which is 1.273 and 2.178 times that of the fused glass body and PIMed bodies, respectively. Moreover, a thermal expansion coefficient of 7.816 × 10⁻⁶/°C is obtained, which coincides with that of the raw glass powder (7.5-8.0 × 10⁻⁶/°C), indicating that the glass body is fully densified after the HIP process.

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• Fabrication and characteristics of Li2TiO3 pebbles manufactured by using powder injection molding (PIM) process
  Young Ah Park, Yi-Hyun Park, Mu-Young Ahn, Young Soo Yoon
  Journal of Nuclear Materials.2024; 597: 155140.     CrossRef
• Combined simulation of micro and nanoparticles in RF inductively coupled plasma torches with the variations of metallic species and feeding nozzle location
  Cheongbin Cheon, Ho Jun Kim, Hae June Lee
  Japanese Journal of Applied Physics.2023; 62(SA): SA1014.     CrossRef
• High-throughput injection molding of transparent fused silica glass
  Markus Mader, Oliver Schlatter, Barbara Heck, Andreas Warmbold, Alex Dorn, Hans Zappe, Patrick Risch, Dorothea Helmer, Frederik Kotz, Bastian E. Rapp
  Science.2021; 372(6538): 182.     CrossRef
• Controlling the sintering response in the development of multilayered components produced via powder injection molding route—a review
  O. J. Ojo-kupoluyi, S. M. Tahir, T. T. Dele-Afolabi, M. S. Anuar
  The International Journal of Advanced Manufacturing Technology.2020; 107(9-10): 3755.     CrossRef
• Fabrication of pressureless sintered Si3N4 ceramic balls by powder injection molding
  Chang Woo Gal, Gi Woung Song, Woon Hyung Baek, Hyung Kyu Kim, Dae Keun Lee, Ki Wook Lim, Seong Jin Park
  Ceramics International.2019; 45(5): 6418.     CrossRef
• Thermal decomposition behavior and modeling of PMN-PZT ceramic feedstock with varying binder compositions
  Jae Man Park, Jun Sae Han, Chang Woo Gal, Joo Won Oh, Dongguo Lin, Jaebum Noh, Kunal H Kate, Sundar V Atre, Youngmoo Kim, Seong Jin Park
  Materials Research Express.2019; 6(6): 065316.     CrossRef
• Powder Injection Molding Process in Industrial Fields
  Joo Won OH, Chang Woo GAL, Daseul SHIN, Jae Man PARK, Woo Seok YANG, Seong Jin PARK
  Journal of the Japan Society of Powder and Powder Metallurgy.2018; 65(9): 539.     CrossRef
• Optimization of Process Condition for Fe Nano Powder Injection Molding
  Joo Won Oh, Won Sik Lee, Seong Jin Park
  Journal of Korean Powder Metallurgy Institute.2017; 24(3): 223.     CrossRef

The sintering mechanisms of nanoscale copper powders have been investigated. A molecular dynamics (MD) simulation with the embedded-atom method (EAM) was employed for these simulations. The dimensional changes for initial-stage sintering such as characteristic lengths, neck growth, and neck angle were calculated to understand the densification behavior of copper nano-powders. Factors affecting sintering such as the temperature, powder size, and crystalline misalignment between adjacent powders have also been studied. These results could provide information of setting the processing cycles and material designs applicable to nano-powders. In addition, it is expected that MD simulation will be a foundation for the multi-scale modeling in sintering process.

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• Mesoscale modelling of polymer powder densification due to thermal sintering
  Amine Bahloul, Issam Doghri, Laurent Adam
  Applied Mathematical Modelling.2023; 114: 408.     CrossRef
• Review of “Integrated Computer-Aided Process Engineering Session in the International Symposium on Innovation in Materials Processing (ISIMP, 26–29 October 2021)”
  Hyunjoo Choi, Jungjoon Kim, Pil-Ryung Cha, Hyoung Seop Kim
  MATERIALS TRANSACTIONS.2023; 64(10): 2542.     CrossRef
• Enhancement in electrical conductivity of pastes containing submicron Ag-coated Cu filler with palmitic acid surface modification
  Eun Byeol Choi, Jong-Hyun Lee
  Applied Surface Science.2017; 415: 67.     CrossRef

Powder injection molding is an important manufacturing technology to mass produce superalloy components with complex shape. Injection molding step is particularly important for realizing a desired shape, which requires much time and efforts finding the optimum process condition. Therefore computer aided engineering can be very useful to find proper injection molding conditions. In this study, we have conducted a finite element method based simulation for the spiral mold test of superalloy feedstock and compared the results with experimental ones. Sensitivity analysis with both of simulation and experiment reveals that the melt temperature of superalloy feedstock is the most important factor for the full filling of mold cavity. The FEM based simulation matches well the experimental results. This study contributes to the optimization of superalloy powder injection molding process.

Citations

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• Powder Injection Molding Process in Industrial Fields
  Joo Won OH, Chang Woo GAL, Daseul SHIN, Jae Man PARK, Woo Seok YANG, Seong Jin PARK
  Journal of the Japan Society of Powder and Powder Metallurgy.2018; 65(9): 539.     CrossRef
• Effect of Diamond Particle Size on the Thermal Shock Property of High Pressure High Temperature Sintered Polycrystalline Diamond Compact
  Ji-Won Kim, Min-Seok Baek, Hee-Sub Park, Jin-Hyeon Cho, Kee-Ahn Lee
  Journal of Korean Powder Metallurgy Institute.2016; 23(5): 364.     CrossRef

A magnetic powder, M-type barium hexaferrite (BaFe12O19), was consolidated with the spark plasma sintering process. Three different holding temperatures, 850°C, 875°C and 900°C were applied to the spark plasma sintering process with the same holding times, heating rates and compaction pressure of 30 MPa. The relative density was measured simultaneously with spark plasma sintering and the convergent relative density after cooling was found to be proportional to the holding temperature. The full relative density was obtained at 900°C and the total sintering time was only 33.3 min, which was much less than the conventional furnace sintering method. The higher holding temperature also led to the higher saturation magnetic moment (σ_s) and the higher coercivity (H_c) in the vibrating sample magnetometer measurement. The saturation magnetic moment (σ_s) and the coercivity (H_c) obtained at 900°C were 56.3 emu/g and 541.5 Oe for each.

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• A study of crystalline – texture and anisotropic properties of hexagonal BaFe12O19 sintered by in-situ magnetic-anisotropy spark plasma sintering (MASPS)
  Haetham G. Mohammed, Thar Mohammed Badri Albarody, Husam Kareem Mohsin Al-Jothery, Mazli Mustapha, N.M Sultan
  Journal of Magnetism and Magnetic Materials.2022; 553: 169268.     CrossRef
• Process Optimization of In Situ Magnetic-Anisotropy Spark Plasma Sintering of M-Type-Based Barium Hexaferrite BaFe12O19
  Haetham G. Mohammed, Thar Mohammed Badri Albarody, Susilawati Susilawati, Soheil Gohari, Aris Doyan, Saiful Prayogi, Muhammad Roil Bilad, Reza Alebrahim, Anwar Ameen Hezam Saeed
  Materials.2021; 14(10): 2650.     CrossRef
• Self-Consolidation and Surface Modification of Mechanical Alloyed Ti-25.0 at.% Al Powder Mixture by Using an Electro-Discharge Technique
  S.Y. Chang, H.S. Jang, Y.H. Yoon, Y.H. Kim, J.Y. Kim, Y.K. Lee, W.H. Lee
  Archives of Metallurgy and Materials.2017; 62(2): 1293.     CrossRef
• Plastic deformation and microstructural evolution during the shock consolidation of ultrafine copper powders
  Dong-Hyun Ahn, Wooyeol Kim, Minju Kang, Lee Ju Park, Sunghak Lee, Hyoung Seop Kim
  Materials Science and Engineering: A.2015; 625: 230.     CrossRef