The Impact of Interface Characteristics on Mechanical Performance of a Hot-Forged Cu/Ti-Coated-Diamond Composite

2021 ◽  
Vol 1016 ◽  
pp. 1682-1689
Author(s):  
Lei Lei ◽  
Leandro Bolzoni ◽  
Fei Yang
Keyword(s):  
High Performance ◽  
Mechanical Performance ◽  
Hot Forging ◽  
Copper Matrix ◽  
Diamond Surface ◽  
Copper Powders ◽  
Tic Particle ◽  
Elemental Copper ◽  
Cold Pressed ◽  
The Impact

The Cu/55vol.%diamond (Ti) composites were fabricated by hot forging of the cold-pressed powder preforms, consisted of elemental copper powders and Ti-coated diamond particles, at 800 °C (800C-Cu/55Dia composite) and 1050 °C (1050C-Cu55Dia composite), respectively. Well bonded interface was achieved between the diamond and the copper matrix for the 800C-Cu/55Dia composite, and the coverage of diamond by interface was about 96%, attributed to homogeneously distributed nanospherical TiC interface formed on the diamond surface. However, obvious coarse TiC particle size and spallation of the formed interface were observed in the 1050C-Cu55Dia composite, implying that the composite had a relatively low bonding strength. The formed chemical bonding, good wettability and strong mechanical interlocking between the diamond and the copper matrix enable the 800C-Cu/55Dia composite having a high tensile strength of 145 MPa and a strain at fracture of 0.35%, which are about 260% and 170% higher than those of the 1050C-Cu55Dia composite, suggesting that the 800C-Cu/55Dia composite has the potential to have a high thermal conductivity and use as high-performance heat sink materials.

scholarly journals Synchronously Strengthen and Toughen Polypropylene Using Tartaric Acid-Modified Nano-CaCO3

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2493
Author(s):  
Junlong Yao ◽  
Hanchao Hu ◽  
Zhengguang Sun ◽  
Yucong Wang ◽  
Huabo Huang ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Impact Toughness ◽  
Tartaric Acid ◽  
High Performance ◽  
Mechanical Performance ◽  
Low Cost ◽  
Complexing Agent ◽  
Environmental Technology ◽  
The Impact ◽  
First Time

In order to overcome the challenge of synchronously strengthening and toughening polypropylene (PP) with a low-cost and environmental technology, CaCO3 (CC) nanoparticles are modified by tartaric acid (TA), a kind of food-grade complexing agent, and used as nanofillers for the first time. The evaluation of mechanical performance showed that, with 20 wt.% TA-modified CC (TAMCC), the impact toughness and tensile strength of TAMCC/PP were 120% and 14% more than those of neat PP, respectively. Even with 50 wt.% TAMCC, the impact toughness and tensile strength of TAMCC/PP were still superior to those of neat PP, which is attributable to the improved compatibility and dispersion of TAMCC in a PP matrix, and the better fluidity of TAMCC/PP nanocomposite. The strengthening and toughening mechanism of TAMCC for PP involves interfacial debonding between nanofillers and PP, and the decreased crystallinity of PP, but without the formation of β-PP. This article presents a new applicable method to modify CC inorganic fillers with a green modifier and promote their dispersion in PP. The obtained PP nanocomposite simultaneously achieved enhanced mechanical strength and impact toughness even with high content of nanofillers, highlighting bright perspective in high-performance, economical, and eco-friendly polymer-inorganic nanocomposites.

scholarly journals Machine learning applied to X-ray tomography as a new tool to analyze the voids in RRP Nb3Sn wires

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
T. Bagni ◽  
G. Bovone ◽  
A. Rack ◽  
D. Mauro ◽  
C. Barth ◽  
...  
Keyword(s):  
Machine Learning ◽  
Particle Physics ◽  
High Performance ◽  
Mechanical Performance ◽  
Learning Algorithm ◽  
Copper Matrix ◽  
Analysis Tool ◽  
Key Factors ◽  
X Ray ◽  
Micro Tomography

AbstractThe electro-mechanical and electro-thermal properties of high-performance Restacked-Rod-Process (RRP) Nb3Sn wires are key factors in the realization of compact magnets above 15 T for the future particle physics experiments. Combining X-ray micro-tomography with unsupervised machine learning algorithm, we provide a new tool capable to study the internal features of RRP wires and unlock different approaches to enhance their performances. Such tool is ideal to characterize the distribution and morphology of the voids that are generated during the heat treatment necessary to form the Nb3Sn superconducting phase. Two different types of voids can be detected in this type of wires: one inside the copper matrix and the other inside the Nb3Sn sub-elements. The former type can be related to Sn leaking from sub-elements to the copper matrix which leads to poor electro-thermal stability of the whole wire. The second type is detrimental for the electro-mechanical performance of the wires as superconducting wires experience large electromagnetic stresses in high field and high current conditions. We analyze these aspects thoroughly and discuss the potential of the X-ray tomography analysis tool to help modeling and predicting electro-mechanical and electro-thermal behavior of RRP wires and optimize their design.

Interfacial bonding of chromium-doped copper/diamond composites fabricated by powder metallurgy method

2019 ◽  
Vol 34 (01n03) ◽  
pp. 2040050 ◽  
Author(s):  
Shanquan Jia ◽  
Yu Su ◽  
Leandro Bolzoni ◽  
Fei Yang
Keyword(s):  
Interfacial Layer ◽  
Electronic Devices ◽  
Hot Forging ◽  
Copper Matrix ◽  
Interface Layer ◽  
Interface Structure ◽  
Diamond Surface ◽  
Powder Metallurgy Method ◽  
Power Electronic ◽  
Diamond Particles

Copper/diamond composites can be used as heat-sink materials for high-power electronic devices due to their potential high thermal conductivity. However, it is challenging to obtain well-bonded interface between the copper matrix and the diamond particles. In this paper, we fabricated copper/diamond composites with [Formula: see text] wt.% of chromium additive ([Formula: see text], 3 and 7.4, and the corresponding composite was referred to as 1Cr-Cu/Dia, 3Cr-Cu/Dia and 7Cr-Cu/Dia, respectively) by hot forging of powder preforms. Results showed that only Cr3C2 interfacial layer formed between the copper matrix and the diamond particles for the 1Cr-Cu/Dia and 3Cr-Cu/Dia composites with a thickness of about 100 and 500 nm, respectively. A Cr/Cr3C2 dual layer interface formed in the 7Cr-Cu/Dia composite and its thickness was [Formula: see text]m. The coverage of diamond surface by the interface layer increased with increasing the adding amount of chromium in the composites. The 3Cr-Cu/Dia composite achieved the highest relative density and bonding strength, comparing to 1Cr-Cu/Dia and 7Cr-Cu/Dia composites, attributed to the formation of an optimal interface structure.

scholarly journals Fabrication of High-Performance Bamboo–Plastic Composites Reinforced by Natural Halloysite Nanotubes

Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2259
Author(s):  
Xiaobei Jin ◽  
Jingpeng Li ◽  
Rong Zhang ◽  
Zehui Jiang ◽  
Daochun Qin
Keyword(s):  
Thermal Stability ◽  
High Performance ◽  
Moisture Absorption ◽  
Mechanical Performance ◽  
Halloysite Nanotubes ◽  
Industrial Applications ◽  
High Concentration ◽  
Morphological Studies ◽  
Plastic Composites ◽  
The Impact

Bamboo-plastic composites (BPCs) as new biomass-plastic composites have recently attracted much attention. However, weak mechanical performance and high moisture absorption as well as low thermal stability greatly limit their industrial applications. In this context, different amounts of halloysite nanotubes (HNTs) were used as a natural reinforcing filler for BPCs. It was found that the thermal stability of BPCs increased with increasing HNT contents. The mechanical strength of BPCs was improved with the increase in HNT loading up to 4 wt% and then worsened, while the impact strengths were slightly reduced. Low HNT content (below 4 wt%) also improved the dynamic thermomechanical properties and reduced the water absorption of the BPCs. Morphological studies confirmed the improved interfacial compatibility of the BPC matrix with 4 wt% HNT loading, and high-concentration HNT loading (above 6 wt%) resulted in easy agglomeration. The results highlight that HNTs could be a feasible candidate as nanoreinforcements for the development of high-performance BPCs.

scholarly journals Additive Manufacturing and Injection Moulding of High-Performance IF-WS2/PEEK Nanocomposites: A Comparative Study

2021 ◽  
Vol 8 ◽  
Author(s):  
Atefeh Golbang ◽  
Mozaffar Mokhtari ◽  
Eileen Harkin-Jones ◽  
Edward Archer ◽  
Alistair Mcilhagger
Keyword(s):  
Mechanical Properties ◽  
Injection Moulding ◽  
High Performance ◽  
Mechanical Performance ◽  
Particle Dispersion ◽  
Fused Deposition Modelling ◽  
Fused Deposition ◽  
3D Printed ◽  
Interlayer Bonding ◽  
The Impact

In this study, PEEK nanocomposites with 0, 0.5, 1, and 2wt% IF-WS2 were manufactured by injection moulding and Fused Deposition Modelling (FDM). To compare the impact of the two processing methods and the incorporated nanoparticles on the morphology, crystallization and final mechanical properties of the nanocomposites, SEM, DSC and tensile testing were performed. In general, a good distribution of nanoparticles was observed in PEEK, although larger agglomerates were visible at 2 wt% IF-WS2. The crystallization degree of PEEK increased with increasing loading of IF-WS2 nanoparticles up to 1wt% and then declined at 2 wt%, due to lower level of particle dispersion in this sample. The 3D printed samples showed slightly higher crystallinity at each IF-WS2 loading in relation to the injection moulded samples and extruded filaments, because of multiple reheating effect from subsequent layer deposition during FDM, causing recrystallization. In general, incorporation of IF-WS2 nanoparticles increased the mechanical properties of pure PEEK in both 3D printed and injection moulded samples. However, this increment was more noticeable in the 3D-printed nanocomposite samples, resulting in smaller gap between the mechanical properties of the 3D-printed samples and the injection moulded counterparts, in respect to pure PEEK, particularly at 1 wt% IF-WS2. This effect is ascribed to the increased inter-layer bonding of PEEK in the presence of IF-WS2 nanoparticles in FDM. In general, the lower mechanical properties of the 3D printed samples compared with the injection moulded ones are ascribed to poor interlayer bonding between the deposited layers and the presence of voids. However, addition of just 1 wt% of IF-WS2 nanoparticles into PEEK increased the tensile strength and Young’s modulus of the FDM PEEK materials to similar levels to those achieved for unfilled injection moulded PEEK. Therefore, incorporation of IF-WS2 nanoparticles into PEEK is a useful strategy to improve the mechanical performance of FDM PEEK.

scholarly journals THE EFFECT OF MICRO-SILICA ON THE MICROSCOPIC FEATURES OF THE UHPC COMPOSITE AND ITS INTER-FACIAL TRANSITION ZONE

2018 ◽  
Vol 15 ◽  
pp. 31-35 ◽  
Author(s):  
Vladimír Hrbek ◽  
Zdeněk Prošek ◽  
Roman Chylík ◽  
Lukáš Vráblík
Keyword(s):  
Transition Zone ◽  
High Performance ◽  
Mechanical Performance ◽  
High Performance Concrete ◽  
Ultra High Performance Concrete ◽  
Microscopic Features ◽  
Cement Binder ◽  
Micro Silica ◽  
The Impact ◽  
Silica Additive

The uplift of concrete overall macroscopic performance by way of alternative additives is commonly used technique. In case of ultra high performance concrete (UHPC), micro-silica is added to the mixture as a micro-filler to the structure of cement binder. As a result, the cementitious matrix macro-mechanical performance is elevated. This paper is aimed on the UHPC micro-scale enhancement by different micro-silica additive content in the mixture. More closely, the study investigate the impact of the micro-silica on the inter-facial transition zone (ITZ) between the binder matrix and basaltic aggregate.

Dietary Vitamin and Stability of Oral Anticoagulation: Proposal of a Diet with Constant Vitamin K1 Content

1997 ◽  
Vol 77 (03) ◽  
pp. 504-509 ◽  
Author(s):  
Sarah L Booth ◽  
Jacqueline M Charnley ◽  
James A Sadowski ◽  
Edward Saltzman ◽  
Edwin G Bovill ◽  
...  
Keyword(s):  
Dietary Intake ◽  
Vitamin K ◽  
High Performance ◽  
Case Reports ◽  
Food Composition ◽  
Dietary Guidelines ◽  
Dietary Vitamin ◽  
Vitamin K1 ◽  
The Stability ◽  
The Impact

SummaryCase reports cited in Medline or Biological Abstracts (1966-1996) were reviewed to evaluate the impact of vitamin K1 dietary intake on the stability of anticoagulant control in patients using coumarin derivatives. Reported nutrient-drug interactions cannot always be explained by the vitamin K1 content of the food items. However, metabolic data indicate that a consistent dietary intake of vitamin K is important to attain a daily equilibrium in vitamin K status. We report a diet that provides a stable intake of vitamin K1, equivalent to the current U.S. Recommended Dietary Allowance, using food composition data derived from high-performance liquid chromatography. Inconsistencies in the published literature indicate that prospective clinical studies should be undertaken to clarify the putative dietary vitamin K1-coumarin interaction. The dietary guidelines reported here may be used in such studies.

Microstructural and Mechanical Behaviour Evaluation of Mg-Al-Zn Alloy Friction Stir Welded Joint

2020 ◽  
Vol 17 (3) ◽  
pp. 8150-8159
Author(s):  
Kulwant Singh ◽  
Gurbhinder Singh ◽  
Harmeet Singh
Keyword(s):  
Heat Treatment ◽  
Friction Stir Welding ◽  
Magnesium Alloys ◽  
Mechanical Performance ◽  
Fuel Efficiency ◽  
Research Work ◽  
Grain Structure ◽  
Tensile Fracture ◽  
Friction Stir ◽  
The Impact

The weight reduction concept is most effective to reduce the emissions of greenhouse gases from vehicles, which also improves fuel efficiency. Amongst lightweight materials, magnesium alloys are attractive to the automotive sector as a structural material. Welding feasibility of magnesium alloys acts as an influential role in its usage for lightweight prospects. Friction stir welding (FSW) is an appropriate technique as compared to other welding techniques to join magnesium alloys. Field of friction stir welding is emerging in the current scenario. The friction stir welding technique has been selected to weld AZ91 magnesium alloys in the current research work. The microstructure and mechanical characteristics of the produced FSW butt joints have been investigated. Further, the influence of post welding heat treatment (at 260 °C for 1 h) on these properties has also been examined. Post welding heat treatment (PWHT) resulted in the improvement of the grain structure of weld zones which affected the mechanical performance of the joints. After heat treatment, the tensile strength and elongation of the joint increased by 12.6 % and 31.9 % respectively. It is proven that after PWHT, the microhardness of the stir zone reduced and a comparatively smoothened microhardness profile of the FSW joint obtained. No considerable variation in the location of the tensile fracture was witnessed after PWHT. The results show that the impact toughness of the weld joints further decreases after post welding heat treatment.

Alpha Tocopherol Loaded in Liposome: Preparation, Optimization, Characterization and Sperm Motility Protection

2020 ◽  
Vol 10 (3) ◽  
pp. 228-236 ◽  
Author(s):  
Lamia Taouzinet ◽  
Sofiane Fatmi ◽  
Allaeddine Khellouf ◽  
Mohamed Skiba ◽  
Mokrane Iguer-ouada
Keyword(s):  
Vitamin E ◽  
Sperm Motility ◽  
High Performance ◽  
Positive Impact ◽  
Alpha Tocopherol ◽  
Ethanol Injection ◽  
Liposome Preparation ◽  
Liposome Size ◽  
Optimum Solution ◽  
The Impact

Background: Alpha-tocopherol is a potent antioxidant involved in sperm protection particularly during cryopreservation. However, its poor solubility limits the optimal protection in aqueous solutions. Objective: The aim of this study was to enhance the solubility of α-tocopherol by the use of liposomes. Methods: The experimental approach consisted to load vitamin E in liposomes prepared by ethanol injection method and the optimization carried out by an experimental design. The optimum solution was characterized by high performance liquid chromatography and scanning electron microscope. Finely, the impact on sperm motility protection was studied by the freezing technic of bovine sperm. Results: The optimum solution was obtained when using 10.9 mg/ml of phospholipids, 1.7 mg/ml of cholesterol and 2 mg/ml of vitamin E. The liposome size was 99.86 nm, providing 78.47% of loaded efficiency. The results showed also a significant positive impact on sperm motility after hours of preservation. Conclusion: In conclusion, the current results showed the interest of liposome preparation as an alternative to enhance vitamin E solubility and to protect spermatozoa during cryopreservation.

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