| 1. |
- Alinejadian, Navid, et al.
(author)
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Importance of the micro-lattice structure of selective laser melting processed Mo/Mo(x)S(x+1) composite : Corrosion studies on the electrochemical performance in aqueous solutions
- 2022
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In: Materials Today Chemistry. - : Elsevier BV. - 2468-5194. ; 26
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Journal article (peer-reviewed)abstract
- Selective laser melting (SLM) based processing of Mo-based samples is challenging due to solidification cracking. We here demonstrate that the addition of 2 wt% MoS2 to the Mo feedstock markedly improves crack mitigation of SLM-processed Mo/MoS2/Mo2S3 composite micro-lattice structures (SLM-Mo/ Mo(x)S(x+1)). Crack inhibition is suggested to be a result of Mo2S3 formation, decreased lattice strain (0.04 4%), and a decrease in accumulated residual stresses. The increased values of polarization resistance from 42.3 and 19.2 kU cm2 to 437 and 78.2 kU cm2, respectively verified the hindering effect of the composition on stress corrosion cracking (SCC) and surface oxidation cracking. However, an increased corrosion current density, from 1.22 to 10.2 mA/cm2, and cathodic Tafel constant, from 175 to 260.5 mV, confirmed the decreased polarization resistance and occurrence of different types of corrosion such as SCC and pitting. The strategy to add 2 wt% MoS2 to the Mo feedstock enables the fabrication of hightemperature micro-lattice structure components with improved corrosion resistance properties applicable in e.g., electronic, power semiconductor heat sinks, offshore-, aerospace-, defense-, or particularly novel sodium-ion energy storage applications.
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| 2. |
- Maurya, H. S., et al.
(author)
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Additive manufacturing of TiC-based cermets : A detailed comparison with spark plasma sintered samples
- 2023
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In: Journal of Alloys and Compounds. - 0925-8388 .- 1873-4669. ; 960
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Journal article (peer-reviewed)abstract
- The present work is a comparative study on the TiC-430 L ferritic stainless steel (FSS) cermets manufactured via two powder metallurgical processes, namely, conventional spark plasma sintering (SPS) and metal additive manufacturing (AM) process (laser powder-bed fusion process (LPBF)/selective laser melting (SLM)). The rescanning strategy has been used to preheat and melt the powder bed with different laser parameters during the SLM process to suppress the presence of residual thermal stress leading to the fabrication of cermets without cracks. The as-fabricated SPS samples (95 %) show a relatively lower density than the SLM-built parts (~98 %). A study of their mechanical properties such as hardness, compressive strength, and fracture toughness was conducted and discussed in detail. Further, the corrosion behavior of the fabricated cermets parts was evaluated in 3.5 wt% NaCl. The SLM-prepared specimens reveal finer microstructures and better mechanical properties (compressive strength and fracture toughness) due to the presence of fine microstructure. Furthermore, the corrosion current density of TiC-430 L fss-based cermets fabricated by SLM is approximately 270 times lower than that of cermets parts fabricated by SPS, indicating excellent corrosion resistance. On the other hand, the hardness shows an opposite trend, where the SPS samples show the maximum hardness as compared to the SLM counterparts due to the presence of hard and coarse TiC particles along with some metallic carbides formed during the SPS process. The results reveal that AM processes not only can fabricate cermets with intricate shapes but can also fabricate them with improved mechanical and corrosion properties.
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| 3. |
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| 4. |
- Maurya, H. S., et al.
(author)
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Investigation of the tribological behavior of the additively manufactured TiC-based cermets by scratch testing
- 2023
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In: Journal of Alloys and Compounds. - 0925-8388 .- 1873-4669. ; 959
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Journal article (peer-reviewed)abstract
- This study deals with the tribological behavior of the TiC-430 L SS cermets fabricated via an additive manufacturing process such as laser powder bed fusion/selective laser melting. A gradient microstructure (finer and coarser morphology) can be observed in the fabricated parts due to SLM's complex thermal history. Using Rockwell indenter, single and multiple passes scratch tests have been performed as a function of applied load to study the wear mechanism of the binder and matrix phase. A surface 3D profilometer was used to analyze the scratch track variation in terms of scratch width and depth. Scanning Electron microscopy (SEM) analysis was performed on the scratched cermet parts to study the wear mechanism and microstructural analysis. It has been observed that the scratch hardness increases with increasing load and the same decreases with increasing the number of passes. Similarly, the coefficient of friction increases with increasing load. Cermets with complex microstructural features exhibit high wear resistance under low loads and for higher loads, multiple passes can lead to tribolayer formation.
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| 5. |
- Prashanth, K.G., et al.
(author)
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Microstructure and mechanical properties of Al-12Si produced by selective laser melting: Effect of heat treatment
- 2014
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In: Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing. - : Elsevier BV. - 0921-5093 .- 1873-4936. ; 590, s. 153-160
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Journal article (peer-reviewed)abstract
- Al-12Si specimens are produced by selective laser melting (SLM) from gas atomized powders. An extremely fine cellular structure is observed with residual free Si along the cellular boundaries. Room temperature tensile tests reveal a remarkable mechanical behavior: the samples show yield and tensile strengths of about 260. MPa and 380. MPa, respectively, along with fracture strain of ~3%. The effect of annealing on microstructure and related tensile properties is examined and the results demonstrate that the mechanical behavior of the Al-12Si SLM samples can be tuned within a wide range of strength and ductility through proper annealing treatment.
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| 6. |
- Prashanth, K.G., et al.
(author)
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Structural and Mechanical Characterization of Zr 58.5Ti 8.2Cu 14.2Ni 11.4Al 7.7 Bulk Metallic Glass
- 2012
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In: Materials. - : MDPI AG. - 1996-1944. ; 5:1, s. 1-11
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Journal article (peer-reviewed)abstract
- Thermal stability, structure and mechanical properties of the multi-component Zr 58.5Ti 8.2Cu 14.2Ni 11.4Al 7.7 bulk metallic glass have been studied in detail. The glassy material displays good thermal stability against crystallization and a fairly large supercooled liquid region of 52 K. During heating, the alloy transforms into a metastable icosahedral quasicrystalline phase in the first stage of crystallization. At high temperatures, the quasicrystalline phase undergoes a transformation to form tetragonal and cubic NiZr 2-type phases. Room-temperature compression tests of the as-cast sample show good mechanical properties, namely, high compressive strength of about 1,630 MPa and fracture strain of 3.3%. This is combined with a density of 6.32 g/cm 3 and values of Poisson's ratio and Young's modulus of 0.377 and 77 GPa, respectively. The mechanical properties of the glass can be further improved by cold rolling. The compressive strength rises to 1,780 MPa and the fracture strain increases to 8.3% for the material cold-rolled to a diameter reduction of 10%.
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| 7. |
- Shukla, Riddhi, et al.
(author)
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Densification of the eggshell powder by spark plasma sintering
- 2023
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In: Journal of Alloys and Compounds. - : Elsevier. - 0925-8388 .- 1873-4669. ; 962
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Journal article (peer-reviewed)abstract
- Chicken eggshells (eggshells) are the bio-waste produced during day-to-day egg consumption by humans. The eggshell contains calcium carbonate (CaCO3) along with several other elements such as Si, Mg, K, P, Na, etc., which enables its application for human bio-implants. Our research work aims to practically implement the eggshell powder as the bio-implant, for which, the study of the densification behavior of the eggshell powder is required. Hence, the present paper represents the densification behavior of the crystalline eggshell powder by spark plasma sintering. The eggshell powders were irregular in shape with a wide particle size distribution. The eggshell powder was sintered at six varying temperatures, i.e., 250 °C, 500 °C, 750 °C, 850 °C, 900 °C, and 1000 °C. The consolidated samples were characterized through SEM, FTIR, and XRD analysis, and the optimum spark plasma sintering temperature was determined. The consolidation of eggshells at 850 °C not only avoids the calcination process (due to the application of pressure) but gives optimum density and hardness making it an optimum condition for consolidating eggshells into compacts.
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| 8. |
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| 9. |
- Ummethala, Raghunandan, et al.
(author)
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In Vitro Corrosion Behavior of Selective Laser Melted Ti-35Nb-7Zr-5Ta
- 2021
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In: Journal of materials engineering and performance (Print). - : Springer Science and Business Media LLC. - 1059-9495 .- 1544-1024.
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Journal article (peer-reviewed)abstract
- Ti-35Nb-7Zr-5Ta (TNZT) alloy has been fabricated by selective laser melting (SLM) at different build orientations with respect to the base plate and the resulting disparities in the grain shape, size, preferred orientations and lattice strains have been determined. Potentiodynamic polarization tests performed under in vitro conditions indicated that the specimens built at 45° orientation showed the highest polarization resistance (24.5 kΩ cm2) and lowest rate of corrosion (0.23 μA cm−2) compared to the specimens built at other orientations. The corrosion behaviors of the SLM specimens have been correlated with their microstructural features and further compared with that of its spark plasma sintered (SPS) counterpart and commercial alloys such as Ti6Al4V and Ti6Al7Nb. Electrochemical impedance spectroscopy and potentiostatic measurements have revealed that the passive film forming on the TNZT sample at 45° orientation is highly stable and more protective than that of the other samples. Auger electron spectroscopy has confirmed that both Ti and Nb participate actively in the passive film formation on the SLM TNZT alloy.
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| 10. |
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