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Keywords = TEM in situ compressive test

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13 pages, 7449 KiB  
Article
A Study on the Microstructure and Mechanical Properties of Improved 25Ni-20Cr Steel via in Situ Testing
by Penghui Lei, Xiaoyu Ji, Jiahao Chen, Yunhao Huang, Nan Lv, Yulin Fan, Yongchao Hou, Xinsheng Shi and Di Yun
Nanomaterials 2025, 15(6), 413; https://doi.org/10.3390/nano15060413 - 7 Mar 2025
Viewed by 648
Abstract
To meet the application requirements for structural components in Gen-IV nuclear reactors, it is essential to improve the high-temperature mechanical properties of 25Ni-20Cr (S35140) austenitic stainless steel. In this research, an improved austenitic stainless steel (N-S35140), derived from S35140 steel, was investigated. The [...] Read more.
To meet the application requirements for structural components in Gen-IV nuclear reactors, it is essential to improve the high-temperature mechanical properties of 25Ni-20Cr (S35140) austenitic stainless steel. In this research, an improved austenitic stainless steel (N-S35140), derived from S35140 steel, was investigated. The scanning transmission electron microscopy (STEM) results indicate that the addition of titanium (Ti) microalloying elements to S35140 steel led to the precipitation of new strengthening nano phases, including M(C, N), MC, MN and Ti(C, N), in N-S35140. These precipitates effectively compensated for the loss of high-temperature strength resulting from the substantial reduction in carbon content. During the in situ transmission electron microscopy (TEM) compressive process at room temperature, the yield strength of N-S35140 steel is 618.4 MPa. At room temperature, the tensile strength of N-S35140 steel is 638.5 MPa, with a yield strength of 392.8 MPa and an elongation of 32.7%, which surpasses those of S35140 steel at room temperature. N-S35140 steel exhibits a tensile strength of 330.6 MPa, a yield strength of 228.2 MPa, and an elongation of 51.4% during the in situ scanning electron microscopy (SEM) tensile test conducted at 650 °C. As a consequence, the improved N-S35140 steel demonstrates significantly enhanced mechanical properties compared to the original S35140 steel, positioning it as a promising candidate for structural components in Gen-IV nuclear reactors. Full article
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16 pages, 12609 KiB  
Article
Microstructure and Micro-Mechanical Properties of Thermally Sprayed HA-TiO2 Coating on Beta-Titanium Substrate
by Abdulaziz Kurdi, Doaa Almalki, Ahmed Degnah and Animesh Kumar Basak
Materials 2025, 18(3), 540; https://doi.org/10.3390/ma18030540 - 24 Jan 2025
Viewed by 991
Abstract
Metallic biomaterials in a solid form cause stress-shielding in orthopedic applications. Such implants also suffer from limited tissue attachment to become a part of the living system. In view of that, hydroxyapatite (HA) coating reinforced with titanium oxide (TiO2) was deposited [...] Read more.
Metallic biomaterials in a solid form cause stress-shielding in orthopedic applications. Such implants also suffer from limited tissue attachment to become a part of the living system. In view of that, hydroxyapatite (HA) coating reinforced with titanium oxide (TiO2) was deposited in a beta (β)-Titanium (Ti-35Nb-7Ta-5Zr) substrate by plasma spray. This allows us to exploit the best of the two materials, namely the relatively low modulus of β-Ti, together with the porous and bone-like structure/composition of the HA to facilitate cell growth. This is foreseen to be used as an implant, particularly for musculoskeletal-related disability. Detailed scanning electron microscopy (SEM) investigation shows the lamellar structure of the coating that is composed of different phases and some porosities. Transmission electron microscopy (TEM) confirms the co-existence of both the amorphous and crystalline phases that build up the coating structure. In situ micro-mechanical tests revealed that the HA-TiO2 coating was low in strength and modules compared to that of the substrate material, together with lower ductility. The yield stress and modulus of elasticity of the coating were about 877 ± 174 MPa and 447 ± 24 MPa, respectively. In contrast, the beta (β)-Ti substrate possesses about 990 ± 85 MPa of yield stress and 259 ± 19 MPa modulus of elasticity. The deformation mechanism was also quite different, where the coating crumbled under compressive loading, featuring limited ductility with cleavage (brittle)-type fracture, and the substrate showed plastic flow of materials in the form of slip/shear planes with extended ductility. Full article
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13 pages, 2899 KiB  
Article
Real-Time Observation of Nanoscale Kink Band Mediated Plasticity in Ion-Irradiated Graphite: An In Situ TEM Study
by Melonie P. Thomas, Ryan Schoell, Nahid Sultan Al-Mamun, Winson Kuo, John Watt, William Windes, Khalid Hattar and Aman Haque
Materials 2024, 17(4), 895; https://doi.org/10.3390/ma17040895 - 15 Feb 2024
Cited by 6 | Viewed by 2005
Abstract
Graphite IG-110 is a synthetic polycrystalline material used as a neutron moderator in reactors. Graphite is inherently brittle and is known to exhibit a further increase in brittleness due to radiation damage at room temperature. To understand the irradiation effects on pre-existing defects [...] Read more.
Graphite IG-110 is a synthetic polycrystalline material used as a neutron moderator in reactors. Graphite is inherently brittle and is known to exhibit a further increase in brittleness due to radiation damage at room temperature. To understand the irradiation effects on pre-existing defects and their overall influence on external load, micropillar compression tests were performed using in situ nanoindentation in the Transmission Electron Microscopy (TEM) for both pristine and ion-irradiated samples. While pristine specimens showed brittle and subsequent catastrophic failure, the 2.8 MeV Au2+ ion (fluence of 4.378 × 1014 cm−2) irradiated specimens sustained extensive plasticity at room temperature without failure. In situ TEM characterization showed nucleation of nanoscale kink band structures at numerous sites, where the localized plasticity appeared to close the defects and cracks while allowing large average strain. We propose that compressive mechanical stress due to dimensional change during ion irradiation transforms buckled basal layers in graphite into kink bands. The externally applied load during the micropillar tests proliferates the nucleation and motion of kink bands to accommodate the large plastic strain. The inherent non-uniformity of graphite microstructure promotes such strain localization, making kink bands the predominant mechanism behind unprecedented toughness in an otherwise brittle material. Full article
(This article belongs to the Special Issue Advanced Characterization Techniques on Nuclear Fuels and Materials)
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25 pages, 13057 KiB  
Article
Developing of Lead/Polyurethane Micro/Nano Composite for Nuclear Shielding Novel Supplies: γ-Spectroscopy and FLUKA Simulation Techniques
by Ahmed M. El-Khatib, Mahmoud I. Abbas, Mohamed E. Mahmoud, Mohammed Fayez-Hassan, Mirvat F. Dib, Mamdouh H. Khalil and Ahmed Abd El Aal
Polymers 2023, 15(22), 4416; https://doi.org/10.3390/polym15224416 - 15 Nov 2023
Cited by 5 | Viewed by 2022
Abstract
In this work, the effect of adding Pb nano/microparticles in polyurethane foams to improve thermo-physical and mechanical properties were investigated. Moreover, an attempt has been made to modify the micron-sized lead metal powder into nanostructured Pb powder using a high-energy ball mill. Two [...] Read more.
In this work, the effect of adding Pb nano/microparticles in polyurethane foams to improve thermo-physical and mechanical properties were investigated. Moreover, an attempt has been made to modify the micron-sized lead metal powder into nanostructured Pb powder using a high-energy ball mill. Two types of fillers were used, the first is Pb in micro scale and the second is Pb in nano scale. A lead/polyurethane nanocomposite is made using the in-situ polymerization process. The different characterization techniques describe the state of the dispersion of fillers in foam. The effects of these additions in the foam were evaluated, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) have all been used to analyze the morphology and dispersion of lead in polyurethane. The findings demonstrate that lead is uniformly distributed throughout the polyurethane matrix. The compression test demonstrates that the inclusion of lead weakens the compression strength of the nanocomposites in comparison to that of pure polyurethane. The TGA study shows that the enhanced thermal stability is a result of the inclusion of fillers, especially nanofillers. The shielding efficiency has been studied, MAC, LAC, HVL, MFP and Zeff were determined either experimentally or by Monte Carlo calculations. The nuclear radiation shielding properties were simulated by the FLUKA code for the photon energy range of 0.0001–100 MeV. Full article
(This article belongs to the Special Issue Polymer Nanoparticles: Synthesis and Applications—2nd Edition)
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12 pages, 3973 KiB  
Article
Effects of Melt Hydrogenation on the Microstructure Evolution and Hot Deformation Behavior of TiBw/Ti-6Al-4V Composites
by Hui Yan, Liang Wang, Xiaoming Wang, Botao Jiang, Hongcan Liu, Binbin Wang, Liangshun Luo, Yanqing Su, Jingjie Guo and Hengzhi Fu
Materials 2023, 16(6), 2496; https://doi.org/10.3390/ma16062496 - 21 Mar 2023
Cited by 6 | Viewed by 1752
Abstract
In this study, Ti-6Al-4V matrix composites reinforced with TiB ceramic whiskers were in situ synthesized and hydrogenated using the melt hydrogenation technique (MHT). The effects of MHT on the microstructure evolution and hot compression behavior of the composites were investigated by optical microscopy [...] Read more.
In this study, Ti-6Al-4V matrix composites reinforced with TiB ceramic whiskers were in situ synthesized and hydrogenated using the melt hydrogenation technique (MHT). The effects of MHT on the microstructure evolution and hot compression behavior of the composites were investigated by optical microscopy (OM), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM). Hot compression tests were performed at strain rates of 0.1/s, 0.01/s, and 0.001/s and temperatures of 800 °C, 850 °C, and 900 °C; the hot workability of composites significantly improved after hydrogenation, for example, the 900 °C peak flow stress of hydrogenated composites (43 MPa) decreased by 53.76% compared with that of unhydrogenated ones (93 MPa) at a strain rate of 0.01/s. Microstructural observations show that MHT can effectively facilitate the dispersion of TiB whiskers and induce the α/β lath refinement of the matrix in our as-cast hydrogenated composite. During hot compression, MHT effectively promoted the as-cast composite microstructure refinement, accelerated the dynamic recrystallization (DRX) generation, and reduced the stress concentration at the interface between the reinforcement and matrix; in turn, the hydrogenated composites presented low peak stress during hot compression. Full article
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12 pages, 3374 KiB  
Article
Cyclic Buckling Characterization of an Individual MWCNT Using Quantitative In Situ TEM Axial Compression
by Raz Samira, Adam Cohen, Fernando Patolsky and Noa Lachman
Nanomaterials 2023, 13(2), 301; https://doi.org/10.3390/nano13020301 - 11 Jan 2023
Cited by 1 | Viewed by 1923
Abstract
Carbon nanotubes (CNTs) are extremely conductive and flexible, making them ideal for applications such as flexible electronics and nanoelectromechanical systems. However, in order to properly apply them in such devices, their long-term durability must be assessed. In the present study, we demonstrate cyclic [...] Read more.
Carbon nanotubes (CNTs) are extremely conductive and flexible, making them ideal for applications such as flexible electronics and nanoelectromechanical systems. However, in order to properly apply them in such devices, their long-term durability must be assessed. In the present study, we demonstrate cyclic loading of a thick MWCNT (175 nm) under axial compression, observed in situ under a transmission electron microscope (TEM). The force was applied via controlled displacement, while real-time TEM videos of the deformation process were gathered to produce the morphological data. The in situ observations combined with force–displacement curves revealed the onset of buckling instabilities, and the elastic limits of the tube were assessed. The MWCNT retained its original structure even after 68 loading–unloading cycles, despite observed clues for structural distortions. The stiffness of the tube, calculated after each loading cycle, was in a 0.15 to 0.28 TPa range—comparable to the literature, which further validates the measurement set-up. These in situ tests demonstrate the resilience of CNTs to fatigue which can be correlated with the CNTs’ structure. Such correlations can help tailoring CNTs’ properties to specific applications. Full article
(This article belongs to the Special Issue Mechanics of Nanomaterials and Low-Dimensional Materials)
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12 pages, 13680 KiB  
Article
Morphology and Mechanical Properties of Fossil Diatom Frustules from Genera of Ellerbeckia and Melosira
by Qiong Li, Jürgen Gluch, Zhongquan Liao, Juliane Posseckardt, André Clausner, Magdalena Łępicka, Małgorzata Grądzka-Dahlke and Ehrenfried Zschech
Nanomaterials 2021, 11(6), 1615; https://doi.org/10.3390/nano11061615 - 20 Jun 2021
Viewed by 3208
Abstract
Fossil frustules of Ellerbeckia and Melosira were studied using laboratory-based nano X-ray tomography (nano-XCT), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS). Three-dimensional (3D) morphology characterization using nondestructive nano-XCT reveals the continuous connection of fultoportulae, tube processes and protrusions. The study confirms [...] Read more.
Fossil frustules of Ellerbeckia and Melosira were studied using laboratory-based nano X-ray tomography (nano-XCT), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS). Three-dimensional (3D) morphology characterization using nondestructive nano-XCT reveals the continuous connection of fultoportulae, tube processes and protrusions. The study confirms that Ellerbeckia is different from Melosira. Both genera reveal heavily silicified frustules with valve faces linking together and forming cylindrical chains. For this cylindrical architecture of both genera, valve face thickness, mantle wall thickness and copulae thickness change with the cylindrical diameter. Furthermore, EDS reveals that these fossil frustules contain Si and O only, with no other elements in the percentage concentration range. Nanopores with a diameter of approximately 15 nm were detected inside the biosilica of both genera using TEM. In situ micromechanical experiments with uniaxial loading were carried out within the nano-XCT on these fossil frustules to determine the maximal loading force under compression and to describe the fracture behavior. The fracture force of both genera is correlated to the dimension of the fossil frustules. The results from in situ mechanical tests show that the crack initiation starts either at very thin features or at linking structures of the frustules. Full article
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12 pages, 9348 KiB  
Article
In-Situ Synthesis, Microstructure, and Mechanical Properties of TiB2-Reinforced Fe-Cr-Mn-Al Steel Matrix Composites Prepared by Spark Plasma Sintering
by Jian Liu, Min Wu, Jian Chen, Zibo Ye, Cheng Lin, Weiping Chen and Canyi Du
Materials 2021, 14(9), 2346; https://doi.org/10.3390/ma14092346 - 30 Apr 2021
Cited by 4 | Viewed by 2241
Abstract
In-situ synthesis, microstructure, and mechanical properties of four TiB2-Reinforced Fe-Cr-Mn-Al Steel Matrix Composites have been researched in this work. The microstructure and phases of the prepared specimens have been characterized by using scanning electron microscopy (SEM), X-ray diffraction technique, and transmission [...] Read more.
In-situ synthesis, microstructure, and mechanical properties of four TiB2-Reinforced Fe-Cr-Mn-Al Steel Matrix Composites have been researched in this work. The microstructure and phases of the prepared specimens have been characterized by using scanning electron microscopy (SEM), X-ray diffraction technique, and transmission electron microscopy (TEM). The sintered specimens consisted of Fe2AlCr, CrFeB-type boride, and TiB2. The mechanical properties, such as hardness and compression strength at room temperature (RT) and at elevated temperatures (600 °C and 800 °C) have been evaluated. The compressive strength and Vickers hardness of the sintered specimens increase with the volume fraction of TiB2 in the matrix, which are all much higher than those of the ex-situ TiB2/Fe-15Cr-20Mn-8Al composites and the reported TiB2/Fe-Cr composites with the same volume fraction of TiB2. The highest Vickers hardness and compressive strength at room temperature are 1213 ± 35 HV and 3500 ± 20 MPa, respectively. As the testing temperature increases to 600 °C, or even 800 °C, these composites still show relatively high compressive strength. Precipitation strengthening of CrFeB and in-situ synthesis of TiB2 as well as nanocrystalline microstructure produced by the combination of mechanical alloying (MA) and spark plasma sintering (SPS) can account for the high Vickers hardness and compressive strength. Full article
(This article belongs to the Collection Additive Manufacturing: Alloy Design and Process Innovations)
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13 pages, 23740 KiB  
Article
Incorporation of In Situ Synthesized Nano-Copper Modified Phenol-Formaldehyde Resin to Improve the Mechanical Properties of Chinese Fir: A Preliminary Study
by Fan Li, Cuiyin Ye, Yanhui Huang, Xianmiao Liu and Benhua Fei
Polymers 2021, 13(6), 876; https://doi.org/10.3390/polym13060876 - 12 Mar 2021
Cited by 11 | Viewed by 2526
Abstract
Phenol-formaldehyde (PF) resin, modified using nano-copper with varying contents (0 wt%, 1 wt%, 3 wt%), was manufactured to improve the mechanical properties of Chinese fir. The morphology, chemical, micromechanical and micromechanical properties of the samples were determined by transmission electron microscopy (TEM), atomic [...] Read more.
Phenol-formaldehyde (PF) resin, modified using nano-copper with varying contents (0 wt%, 1 wt%, 3 wt%), was manufactured to improve the mechanical properties of Chinese fir. The morphology, chemical, micromechanical and micromechanical properties of the samples were determined by transmission electron microscopy (TEM), atomic force microscopy (AFM), environmental scanning electron microscopy (ESEM), Fourier transform infrared spectroscopy (FTIR), nanoindentation (NI) and traditional mechanical testing. The TEM and AFM results indicated that the in situ synthesized nano-copper particles were well-dispersed, and spherical, with a diameter of about 70 nm in PF resin. From the FTIR chemical changes detected by FTIR inferred that the nano-copper modified PF resin penetrated into the Chinese fir cell walls and interacted with the acetyl groups of hemicellulose by forming a crosslinked structure. Accordingly, the micro-mechanical properties of the Chinese fir cell walls were enhanced after treatment with nano-copper modified PF resin. The filling of the PF-1-Cu resin (1 wt% nano-copper) in the wood resulted in 13.7% and 22.2% increases in the elastic modulus (MOE) and hardness, respectively, of the cell walls. Besides, the impact toughness and compressive strength of the Chinese fir impregnated with PF-1-Cu resin were 21.8% and 8.2% higher than that of the PF-0-Cu resin. Therefore, in situ synthesized nano-copper-modified PF resin is a powerful treatment method for Chinese fir due to improved diffusive properties and reinforcement of the mechanical properties. Full article
(This article belongs to the Section Polymer Chemistry)
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12 pages, 12222 KiB  
Article
Experimental and Molecular Dynamic Study of Grain Refinement and Dislocation Substructure Evolution in HSLA and IF Steels after Severe Plastic Deformation
by Krzysztof Muszka, Dawid Zych, Paulina Lisiecka-Graca, Lukasz Madej and Janusz Majta
Metals 2020, 10(9), 1122; https://doi.org/10.3390/met10091122 - 21 Aug 2020
Cited by 18 | Viewed by 2702
Abstract
In this study, large-scale molecular dynamic simulations were performed to analyze the dislocation substructure interaction with various types of obstacles present in microalloyed steels during severe plastic deformation. Specifically, fully functional numerical models of the atomic upsetting test were developed, with particular emphasis [...] Read more.
In this study, large-scale molecular dynamic simulations were performed to analyze the dislocation substructure interaction with various types of obstacles present in microalloyed steels during severe plastic deformation. Specifically, fully functional numerical models of the atomic upsetting test were developed, with particular emphasis on the presence of precipitates inside the microstructure grains. The obtained results compared with the microstructural tests, performed using Electron Backscatter Diffraction (EBSD) and Transmission Electron Microscope (TEM) techniques, allowed for a more accurate assessment of the microstructure refinement mechanisms by means of the in-situ recrystallization effect in the deformed samples subjected to the multi-axis compression using the MaxStrain system (Dynamic Systems Inc., New York, NY, USA). Full article
(This article belongs to the Section Metal Casting, Forming and Heat Treatment)
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24 pages, 26002 KiB  
Article
Multi-Analytical Characterization of Corvins’ Castle—Deserted Tower. Construction Materials and Conservation Tests
by Rodica Mariana Ion, Lorena Iancu, Madalina Elena David, Ramona Marina Grigorescu, Bogdan Trica, Raluca Somoghi, Sorina Florentina Vasile, Ioana Daniela Dulama, Anca Irina Gheboianu and Sorin Tincu
Heritage 2020, 3(3), 941-964; https://doi.org/10.3390/heritage3030051 - 20 Aug 2020
Cited by 8 | Viewed by 6339
Abstract
The aim of this paper is to analyze the construction materials (mortars) of an architectural monument (Deserted Tower (Lilly Tower) from Corvins’ Castle, Romania). The mortars were characterized following a multidisciplinary approach, combining macroscopic observation with petrographic microscopy, mineralogical analysis (X-ray diffraction) and [...] Read more.
The aim of this paper is to analyze the construction materials (mortars) of an architectural monument (Deserted Tower (Lilly Tower) from Corvins’ Castle, Romania). The mortars were characterized following a multidisciplinary approach, combining macroscopic observation with petrographic microscopy, mineralogical analysis (X-ray diffraction) and elemental analysis (X-ray fluorescence), hydric properties, and color of representative samples of the monument. The results revealed the use of gypsum mortars (produced by lumps with higher Fe content), with minor concentrations of crystalline dolomites of the Southern Carpathians, calcite, and quartz. The materials’ effective porosity and their water absorption capacity were high. A possible solution to consolidate the damaged area with some consolidation products (hydroxyapatite carbonate and its derivatives with Ag and Sr) was investigated, too. The interactions between the mortar’s specimens and the effectiveness of the consolidation treatments were evaluated by physico-chemical analyses (molecular structure by X-ray powder diffraction (XRPD), wavelength dispersive X-ray fluorescence (WDXRF), dynamic light scattering (DLS)), morphological characterization by microscopic techniques as SEM-EDS, TEM, and physical and mechanical investigations (peeling test and compressive strength). Results were drawn based on historical, in situ observations, and analytical data, and put into evidence the composition, high weathering degree, and the possibility to surface consolidate with Sr-CHAp. Full article
(This article belongs to the Special Issue Assessment and Protection of Cultural Heritage Masonry Structures)
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11 pages, 67234 KiB  
Article
Microstructure and Mechanical Behaviors of Titanium Matrix Composites Containing In Situ Whiskers Synthesized via Plasma Activated Sintering
by Yi Sun, Jian Zhang, Guoqiang Luo, Qiang Shen and Lianmeng Zhang
Materials 2018, 11(4), 544; https://doi.org/10.3390/ma11040544 - 2 Apr 2018
Cited by 17 | Viewed by 4369
Abstract
In this paper, titanium matrix composites with in situ TiB whiskers were synthesized by the plasma activated sintering technique; crystalline boron and amorphous boron were used as reactants for in situ reactions, respectively. The influence of the sintering process and the crystallography type [...] Read more.
In this paper, titanium matrix composites with in situ TiB whiskers were synthesized by the plasma activated sintering technique; crystalline boron and amorphous boron were used as reactants for in situ reactions, respectively. The influence of the sintering process and the crystallography type of boron on the microstructure and mechanical properties of composites were studied and compared. The densities were evaluated using Archimedes’ principle. The microstructure and mechanical properties were characterized by SEM, XRD, EBSD, TEM, a universal testing machine, and a Vickers hardness tester. The prepared composite material showed a high density and excellent comprehensive performance under the PAS condition of 20 MPa at 1000 °C for 3 min. Amorphous boron had a higher reaction efficiency than crystalline boron, and it completely reacted with the titanium matrix to generate TiB whiskers, while there was still a certain amount of residual crystalline boron combining well with the titanium matrix at 1100 °C. The composite samples with a relative density of 98.33%, Vickers hardness of 389.75 HV, compression yield strength of up to 1190 MPa, and an ultimate compressive strength of up to 1710 MPa were obtained. Compared with the matrix material, the compressive strength of TC4 titanium alloy containing crystalline boron and amorphous boron was increased by 7.64% and 15.50%, respectively. Full article
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17 pages, 4408 KiB  
Article
Enhancing the Durability of Calcareous Stone Monuments of Ancient Egypt Using CaCO3 Nanoparticles
by Mohammad A. Aldoasri, Sawsan S. Darwish, Mahmoud A. Adam, Nagib A. Elmarzugi and Sayed M. Ahmed
Sustainability 2017, 9(8), 1392; https://doi.org/10.3390/su9081392 - 10 Aug 2017
Cited by 16 | Viewed by 5953
Abstract
The unwanted changes in valuable historic calcareous stone monuments due to exposure to many physical and chemical effects may lead to its deterioration. The growing interest in the field of conservation of stone monuments encourages the development of consolidation and water-repellent materials. The [...] Read more.
The unwanted changes in valuable historic calcareous stone monuments due to exposure to many physical and chemical effects may lead to its deterioration. The growing interest in the field of conservation of stone monuments encourages the development of consolidation and water-repellent materials. The aim of this study is to evaluate the effectiveness of CaCO3 nanoparticles as a consolidation and protection material for calcareous stone monuments, when those nanoparticles used are dispersed in acrylic copolymer; polyethylmethacrylate (EMA)/methylacrylate (MA) (70/30), respectively. Samples were subjected to artificial aging by relative humidity/temperature to show the optimum conditions of durability and the effectiveness of the nano-mixture in improving the physical and mechanical properties of the stone material. The synthesis process of CaCO3 nanoparticles/polymer nanocomposite has been prepared by in situ emulsion polymerization system. The prepared nanocomposites with 0.15 g CaCO3 nanoparticles showed obvious transparency features and represent nanocomposites coating technology with hydrophobic, consolidating and good protection properties. Some tests were performed in order to estimate the superficial consolidating and protective effect of the treatment. The obtained nanocomposites have been characterized by TEM, while the surface morphology before and after treatment and homogeneous distribution of used consolidation materials on stone surface were examined by SEM. Improvement of stone mechanical properties was evaluated by compressive strength tests. Change in water-interaction properties was evaluated by water absorption capillarity measurements, and colorimetric measurements were used to evaluate the optical appearance. Taken together, the results indicate that CaCO3/polymer nanocomposite is a completely compatible, efficient material for the consolidation of artistic and architectural limestone monuments capable of enhancing the durability of limestone toward artificial aging and improving the stone mechanical properties compared to the samples treated with pure acrylic copolymer without Calcium carbonate nanoparticles. Full article
(This article belongs to the Section Sustainable Chemical Engineering and Technology)
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10 pages, 1425 KiB  
Article
The Microstructural Evolution and Mechanical Properties of Zr-Based Metallic Glass under Different Strain Rate Compressions
by Tao-Hsing Chen and Chih-Kai Tsai
Materials 2015, 8(4), 1831-1840; https://doi.org/10.3390/ma8041831 - 16 Apr 2015
Cited by 23 | Viewed by 7235
Abstract
In this study, the high strain rate deformation behavior and the microstructure evolution of Zr-Cu-Al-Ni metallic glasses under various strain rates were investigated. The influence of strain and strain rate on the mechanical properties and fracture behavior, as well as microstructural properties was [...] Read more.
In this study, the high strain rate deformation behavior and the microstructure evolution of Zr-Cu-Al-Ni metallic glasses under various strain rates were investigated. The influence of strain and strain rate on the mechanical properties and fracture behavior, as well as microstructural properties was also investigated. Before mechanical testing, the structure and thermal stability of the Zr-Cu-Al-Ni metallic glasses were studied with X-ray diffraction (XRD) and differential scanning calorimeter. The mechanical property experiments and microstructural observations of Zr-Cu-Al-Ni metallic glasses under different strain rates ranging from 10−3 to 5.1 × 103 s−1 and at temperatures of 25 °C were investigated using compressive split-Hopkinson bar (SHPB) and an MTS tester. An in situ transmission electron microscope (TEM) nanoindenter was used to carry out compression tests and investigate the deformation behavior arising at nanopillars of the Zr-based metallic glass. The formation and interaction of shear band during the plastic deformation were investigated. Moreover, it was clearly apparent that the mechanical strength and ductility could be enhanced by impeding the penetration of shear bands with reinforced particles. Full article
(This article belongs to the Special Issue Selected Papers from ICETI2014)
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