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•NiTi-SS bimetallic structures built using Wire Arc Additive Manufacturing (WAAM).•Smooth transition in the composition across the joint.•Dendritic microstructure with interface ...showing brittle intermetallic compounds.•Hardness and ultimate strength of joint are 400 HV and 570 MPa, respectively.
Dissimilar joining of Nickel-titanium (NiTi) alloy with other metallic alloys can be used to widen the applications of NiTi for developing artificial bones and joints, guidewires, and stents. This paper presents the microstructure and mechanical properties of Wire Arc Additive Manufactured NiTi-SS bimetallic structures for the first time. Defect-free deposit with a smooth transition in the composition across the joint is observed. NiTi shows a dendritic microstructure and TiCr2, TiNi3 and FeNi intermetallic phases are observed at the interface that imparts reasonable mechanical properties. The interface showed an average hardnes of 400 HV and the ultimate compressive strength is observed to be 570 MPa, with brittle fracture due to the presence of brittle intermetallics.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The powder particle properties in additive manufacturing processes such as selective laser melting (SLM) influence the material properties. The microstructure, hardness, and chemical composition of ...gas-atomized AlCoCrFeNi powder particles were investigated, which showed a biphasic structure, consisting of FCC and BCC with a significant deviation in hardness. SLMed samples, consisting of BCC phase, indicated poor printability, inhomogeneous microstructure, and cracks. Microstructural inhomogeneity of SLM AlCoCrFeNi parts must reflect the inhomogeneity inherited from the atomized powder.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In the present work, combustion synthesis of ZnO nanoparticles using lemon juice and citric acid as fuels has been carried out. A comparative analysis of the obtained powders has been conducted to ...understand the strategic advantages of using lemon juice over citric acid as the combustion fuel for the synthesis of ZnO nanopartilcles. The X-ray diffractograms of both the samples revealed the presence of wurtzite hexagonal structure with the standard JCPDS pattern of zincite 36-1451 with varying crystallite sizes. Surface morphology of the samples was studied by scanning electron microscopy. Particle shapes and sizes were determined by transmission electron microscopy. Although wurtzite hexagonal structures were seen in both the synthesis methods, their morphology and sizes differed significantly with samples prepared by lemon juice presenting smaller size. The band gap energy value determined by Wood-Tauc method was found to be ~ 3.2 eV for both the samples. DPPH assay revealed the antioxidant activity of the samples at varied concentrations. Further, antimicrobial studies were greater for those prepared by lemon juice. Furthermore, trypan blue and MTT assay evaluation of nanoparticles against PC-3, HCT116, A549, and MDA-MB-231 cancer cell lines indicated enhanced anticancer activity of ZnO nanoparticles prepared by lemon juice. It was found that the sample prepared using lemon juice exhibited IC
50
values of 78.80 μg/mL, 28.75 μg/mL, and 10.7 μg/mL, whereas the sample prepared using citric acid as fuel exhibited IC
50
values of 103.6 μg/mL, 41.52 μg/mL, and 20.06 μg/mL, towards PC-3, HCT 116, and MDA-MB-231 respectively.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Mg90Al10–xCex with x=0, 1, 3 and 5 (at%) have been prepared by copper mold casting and the influence of Ce on the microstructure and mechanical properties have been investigated. The addition of 1% ...Ce decreases the volume fraction of the γ-Mg17Al12 phase and with the further increase of Ce to 3% and 5%, the γ-Mg17Al12 intermetallic disappears completely with the formation of the Al11Ce3 and Al2Ce intermetallic phases. The room temperature compression tests show that Ce addition significantly improves the room temperature mechanical properties. For example, the alloy with 5% Ce displays a strength of 448MPa compared to 318MPa of the binary Ce-free alloy along with appreciable plasticity of about 9%. This improvement is due to grain refinement as well as to the precipitation of the Al11Ce3 and Al2Ce strengthening phases.
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IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
A bimodal size metallic glassy particles reinforced 7075 aluminum composite was fabricated by powder metallurgy via ball milling and hot extrusion. The results show that metallic glassy ...reinforcements help to improve the densification due to the liquid-like behavior in the supercooled liquid region. The metallic glassy reinforcements were found to have a bimodal size distribution at nanoscale and microscale, and were uniformly distributed in the matrix. An interphase layer with a thickness of 60–80 nm was observed between the reinforcement/matrix resulted from elemental diffusion and chemical reaction. The introduction of bimodal size metallic glassy particles have significantly improved the mechanical properties, where the yield strength and fracture strength increase from 442 and 648 MPa for Al7075 to 869 and 962 MPa for composite with 17 vol% reinforcement, respectively. The strengthening mechanisms of the composites were revealed.
•Al alloy matrix composites with bimodal-sized metallic glassy reinforcement were produced.•Metallic glassy reinforcements help to improve the densification.•An interphase layer formed due to the elemental diffusion and chemical reaction.•The composites provide a reasonable combination of strength and ductility.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
► Analysis and modeling of mechanical properties of quasicrystal-reinforced composites. ► Quasicrystals remarkably improve the mechanical properties of pure Al. ► Matrix ligament size is the main ...parameter for the strengthening of the composites.
In this work, a model that simultaneously considers the combined strengthening contributions of load bearing, dislocation strengthening and matrix ligament size effects, which has been found to accurately describe the mechanical behavior of Al-based composites reinforced with complex intermetallic particles (Scudino et al. (2009) 8), has been used to predict the mechanical properties of Al-based metal matrix composites containing different amounts of Al62.5Cu25Fe12.5 quasicrystalline reinforcing particles. The present results further demonstrate the validity of this model and confirm the importance of the characteristic matrix ligament size for explaining the strengthening effect of the composites containing large volume fractions of reinforcement.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•Formation of γ-Al12Mg17 intermetallic phase.•Strengthening of the matrix by intermetallic (γ-Al12Mg17) and MgO phases.•Improvement in toughness of the alloy through crack deflection and bridging by ...the γ-Al12Mg17 intermetallic particles.
Highly-dense ultrafine grain Mg–7.4%Al bulk samples with grain size of about 300nm have been produced by powder metallurgy through hot consolidation of mechanically alloyed powders. Room temperature compression tests of the consolidated bulk material reveal remarkable mechanical properties: high compressive strength of about 690MPa combined with a plastic strain exceeding 9%. The high strength of the alloy can be attributed to the combination of three different strengthening mechanisms: grain size refinement, dispersion strengthening and solid solution strengthening. The fracture surface shows trans-granular quasi-cleavage fracture in nature. The MgO rich regions often acted as the microcrack initiation source and thereby stop the main crack. Uniformly distributed intermetallic (γ-Al12Mg17) particles in the matrix deflected main crack and resulted a tortuous crack path. These results demonstrate that powder metallurgy, mechanical alloying combined with hot consolidation is a suitable method for the production of nanostructured Mg-based materials characterized by high strength and considerable plastic deformation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
We describe the synthesis, structural and morphological characteristics of cobalt and nickel doped zinc oxide nanoparticles (ZnO NPs) by solution combustion technique by utilizing lemon juice as ...bio-fuel. Structural parameters were confirmed by the X-ray Rietveld refinement method, all the compounds were crystallized in the wurtzite hexagonal structure with space group P63mc (No. 186). Field emission scanning electron microscopy coupled with energy dispersive X-ray elemental mapping results revealed agglomerated spherical shaped particles and dopant ions were homogeneously distributed. Antibacterial, anticancer, and reactive oxygen species (ROS) generation activities were studied on undoped ZnO-, Co-, and Ni-doped ZnO nanoparticles upon un-exposed/exposed to ultraviolet radiations at 300 nm for 1 h. Antibacterial studies were performed against Salmonella enterica and Clostridium perfringens. Anticancer activity was tested on HeLa and MCF-7 cell lines. Generation of ROS was studied in J744 mouse macrophage cells. Doping of cobalt or nickel in the ZnO lattice enhanced antibacterial, anticancer, and oxidative response generation activities compared to undoped ZnO NPs. These activities were further improved upon exposure to ultraviolet radiations. Together, data indicate a direct activity of ZnO NPs against bacteria, cancer cells and simultaneously boosting host's immunity via inducing activation of immune cells (mouse macrophage cells).
High-entropy alloy, a new generation material, exhibits superior structural properties. For high-temperature applications, where dissimilar materials are in demand, HEAs may be joined with ...commercially available structural materials to improve their performance-life ratio. In this connection, a dissimilar joint was fabricated by gas tungsten arc welding between Al
0.1
CoCrFeNi-HEA and Inconel 718. The columnar dendritic grains are growing epitaxially at the Al
0.1
CoCrFeNi-HEA/weld metal interface, where their compositions are matching. While the composition misfit at the weld metal/Inconel 718 interface, reveals the non-epitaxial mode of solidification. In addition, the fusion zone exhibits the porosity and micro-segregation of NbC and Laves phases. The joint shows a joint efficiency of ~ 88%, where the strength is observed to be 644 MPa with 21% ductility. The results demonstrate the applicability of GTAW in fabricating the dissimilar weld joints between HEA and Inconel 718 for structural applications.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The effect of chemical composition on microstructure and mechanical properties of heavily alloyed beta-titanium Ti-Nb(V)-Cu-Co-Al alloys was studied. The alloys were fabricated by casting into a ...water-cooled copper crucible employing relatively high cooling rates. The microstructure of these alloys consists of primary micrometer-sized bcc-structured (bcc – body centered cubic) dendrites surrounded by a minor amount of intermetallic phases. The morphology and volume fraction of the intermetallic phases are strongly affected by the alloys’ chemical composition. Particularly, the solubility of Cu and Co in the bcc dendrites of Ti-V-Cu-Co-Al is lower compared to that of Ti-Nb-Cu-Co-Al leading to a higher volume fraction of the intermetallic phase in the latter alloy. The high mechanical strength of the Ti-Nb(V)-Cu-Co-Al alloys (yield strength up to 1430 MPa) is mainly attributed to their multiphase nature and solid solution hardening of the supersaturated bcc-structured dendrites. Moreover, the large compressive plastic deformability supported by pronounced strain-hardening reaches several tens of percent. The alloys exhibit a significant strength asymmetry between compressive and tensile loadings, namely, they are weak and brittle under tensile loading. The tensile brittleness is associated with the lattice distortion in the bcc-structured dendrites as well as crack initiation at the interdendritic precipitates.
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IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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