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The spinel nano-ferrites with composition Co0.5Mg0.25Cd0.25Fe2-xCexO4 (0.0 ≤ x ≤ 0.2 with a step interval of 0.05) synthesized by sol-gel auto combustion method. Samples sintered at a significant temperature of 800 °C for 8 h. XRD confirmed the formation of spinel matrix and reduction in lattice constant from 8.3941 A to 8.3598 A by increasing Ce3+ cations. The crystalline size of prepared nano-ferrites reduced from 33.6 nm to 14.5 nm. Two absorption bands in the range of 405.23–435.12 cm−1 for octahedral and 510.85–523.21 cm−1 for the tetrahedral site were detected by using FTIR. The UV–visible study showed the optical band gaps decreased from 3.01 eV to 2.25 eV with decreasing Ce3+ doping. The electrical resistivity of as-prepared nano-ferrites increased in the Ferro region and decreased in the Para region with increasing temperature. The resistivity decreased with Ce3+ doping increase, and drift mobility has an opposite trend of resistivity. Due to the effect of space-charge polarization, the values of the dielectric constant ( e ′ ) and dielectric constant loss ( e ″ ) and tan δ were reduced as the frequency was increased, and displayed a dispersive behavior at higher frequencies.

In bone tissue engineering, multifunctional composite materials are very challenging. Bone tissue engineering is an innovative technique to develop biocompatible scaffolds with suitable orthopedic applications with enhanced antibacterial and mechanical properties. This research introduces a polymeric nanocomposite scaffold based on arabinoxylan-co-acrylic acid, nano-hydroxyapatite (nHAp), nano-aluminum oxide (nAl2O3), and graphene oxide (GO) by free-radical polymerization for the development of porous scaffolds using the freeze-drying technique. These polymeric nanocomposite scaffolds were coated with silver (Ag) nanoparticles to improve antibacterial activities. Together, nHAp, nAl2O3, and GO enhance the multifunctional properties of materials, which regulate their physicochemical and biomechanical properties. Results revealed that the Ag-coated polymeric nanocomposite scaffolds had excellent antibacterial properties and better microstructural properties. Regulated morphological properties and maximal antibacterial inhibition zones were found in the porous scaffolds with the increasing amount of GO. Moreover, the nanosystem and the polymeric matrix have improved the compressive strength (18.89 MPa) and Young's modulus (198.61 MPa) of scaffolds upon increasing the amount of GO. The biological activities of the scaffolds were investigated against the mouse preosteoblast cell lines (MC3T3-E1) and increasing the quantities of GO helps cell adherence and proliferation. Therefore, our findings showed that these silver-coated polymeric nanocomposite scaffolds have the potential for engineering bone tissue.

In this research, an ESC tester machine was built by utilising a fracture mechanics approach. The machine consists of critical components such as an aluminium frame, 3D printed pulley and bracket, DC motor, Arduino microcontroller, and fasteners. The test was performed by securing an acrylic sample using a hook fixed to bracket on the base of the frame and integrated load cell with Arduino microcontroller board. Digital camera was used to capture images with Image J processing software to measure the transient damage area and macro-crack length development at each test condition. The results suggested that the applied load can influence the fracture toughness values. At 55N, the fracture toughness for the acrylic was 1.9 MPa.m1/2 . Increasing the load to 65N, the fracture toughness dropped by 60% to 0.7 MPa.m1/2. The minimum fracture toughness was observed at 85N load; a 91% reduction was recorded. Maximum damage area of 89 mm2 was recorded for sample tested at 55N while minimum damage area was at 85N load, where only 31.81 mm2 area was calculated. It can be concluded that this newly built machine can be used to perform fracture toughness test on polymeric materials under environmental stress cracking (ESC) condition.

Bistable composite laminates are smart composites that have been employed for engineering structures due to their superlative offering of features like ability to change shape and low densities. Because of the embedded geometrical nonlinearity factor, a small variation of input parameters leads to significant changes in the response of the bistable composite laminates. In other words, Uncertainty Quantification (UQ) makes a change in the bistability characteristics. As a result, bistability behavior is extremely reliant on geometrical dimensions and elastic material properties as design parameters. Reliability analysis deals with the quantitative assessment of the occurrence probability due to UQ. In this regard, the reliability and sensitivity analysis of bistable composite plate are investigated through the Monte Carlo Simulation (MCS) and multiple types of uncertain parameters, geometry and material properties, are assumed as random variables. The results indicate bistable composite plates have a high probability to be bistability behavior with the assumed statistical properties. Moreover, the sensitivity reliability analysis illustrates that the thickness and coefficient of thermal expansion have more effect on the bistability behavior in comparison to other input parameters. The results are confirmed by comparing them with those determined by the Finite Element Method (FEM).

Advances in Sustainable Nanocomposites is a newly opened Special Issue of Sustainability, that aims to publish original and review papers on the new scientific development of sustainable nanocomposite materials that are accelerated by zero-carbon policy goals [...]

Bacterial contamination is one of the leading causes of water pollution. Antibacterial polyurethane/cellulose acetate membranes modified by functionalized TiO

Carbon long fiber/copper composites were prepared using electroless and electroplating methods with copper metal for potential aerospace applications. Carbon fibers were heat-treated at 450 &deg, C followed by acid treatment before the metallization processes. Three different methods of metallization processes were applied: electroless silver deposition, electroless copper deposition and electroplating copper deposition. The metallized carbon fibers were subjected to copper deposition via two different routes. The first method was the electroless deposition technique in an alkaline tartrate bath using formaldehyde as a reducing agent of the copper ions from the copper sulphate solution. The second method was conducted by copper electroplating on the chemically treated carbon fibers. The produced carbon fiber/copper composites were extensively investigated by Field-Emission Scanning Electron Microscopy (FE-SEM) supported with an Energy Dispersive X-Ray Analysis (EDAX) unit to analyze the size, surface morphology, and chemical composition of the produced carbon long fiber/copper composites. The results show that the carbon fiber/copper composites prepared using the electroplating method had a coated type surface morphology with good adhesion between the copper coated layer and the surface of the carbon fibers. However, the carbon fiber/copper composites prepared using the electroless deposition had a decorated type morphology. Moreover, it was observed that the metallized carbon fibers using the silver method enhanced the electroless copper coating process with respect to the electroless copper coating process without silver metallization. The electrical conductivity of the carbon fiber/copper composites was improved by metallization of the carbon fibers using silver, as well as by the electrodeposition method.

High uric acid levels cause different clinic conditions. One of them is hyperuricemia, which leads to kidney damage. A solution for eliminating uric acid in the blood is by hemodialysis, which is performed using nanocomposite membranes. In this work, Nylon 6 nanocomposites were synthesized with modified carbon black (MCB), which were considered candidate materials for hemodialysis membranes. The modification of carbon black was made with citric acid using the variable-frequency ultrasound method. The new MCB was characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscopy (TEM), and dispersion tests. Nylon 6/MCB nanocomposites were processed using the ultrasound-assisted melt-extrusion method to improve the dispersion procedure of the nanoparticles. The Nylon 6/MCB nanocomposites were characterized by FTIR, TGA, and differential scanning calorimetry (DSC). These were assessed for the absorption of toxins and hemocompatibility. MBC and nanocomposites showed excellent uric acid removal (78&ndash, 82%) and hemocompatibility (1.6&ndash, 1.8%). These results suggest that Nylon 6/MCB nanocomposites with low loading percentages can be used on a large scale without compatibility problems with blood.

Multiwall carbon nanotube (CNT)-filled high density polyethylene (HDPE) nanocomposites were prepared by extrusion and considered for their suitability in the offshore sheathing applications. Transmission electron microscopy was conducted to analyse dispersion after bulk extrusion. Monolithic and nanocomposite samples were subjected to accelerated weathering and photodegradation (carbonyl and vinyl indices) characterisations, which consisted of heat, moisture (seawater) and UV light, intended to imitate the offshore conditions. The effects of accelerated weathering on mechanical properties (tensile strength and elastic modulus) of the nanocomposites were analysed. CNT addition in HDPE produced environmentally resilient nanocomposites with improved mechanical properties. The energy utilised to extrude nanocomposites was also less than the energy used to extrude monolithic HDPE samples. The results support the mass substitution of CNT-filled HDPE nanocomposites in high-end offshore applications.

Following a comprehensive review of nanocomposite materials and their machinability, this paper details experimental results from the micro-slotting of two different nanocomposites reinforced with graphene platelets and nanoclay fillers as opposed to their base material matrix. The evaluation includes the quality of machined surfaces characterised by SEM, cutting forces monitored using force dynamometry, and surface roughness measured using both contact and non-contact techniques. The evaluation included four filler percentages by weight between 0.1 and 1% in addition to 0% with the plain matrix material. The effect of feed rate is also evaluated at 3 levels (10, 20 and 30 μm/rev) with cutting speed at 4 levels (15.7, 31.4, 62.8 and 94.2 m/min). Dry cutting experiments were performed on an ultra-precision desktop micro-machine tool. Uncoated tungsten carbide end mills 1 mm in dimeter were used in all tests. Surface roughness increased gradually with feed rate while cutting speed had no effect. Ra values ranged from 0.1 – 0.35 μm. Common increases in cutting forces with either feed rate or cutting speed were observed. Forces in general were higher for the material reinforced with 0.3–0.5% nanofiller. Negligible tool wear occurred following the cutting of 140 slots of 100 μm depth (removing 182 mm3 of the material).

Recently, graphene has attracted extensive research interests due to its superior mechanical, electrical and thermal performance. Small loadings of graphene can increase the properties of epoxy significantly. However, because of the large surface area of graphene, it is a challenge to disperse graphene in liquid epoxy. Strong van der Waals force causes reaggregation of graphene in the matrix. As commonly used surfactants, sodium dodecyl sulphate and gum arabic have been used a lot to de-bundle graphene, however, their dispersing efficiencies for graphene in epoxy matrix is unknown. Therefore, to evaluate their dispersing efficiencies, epoxy/graphene nanocomposites had been made and mechanical properties, dynamic mechanical analysis, thermal gravimetric analysis and scanning electron microscopy tests of nanocomposites had been conducted. The results show that the properties of nanocomposites had been enhanced largely after using sodium dodecyl sulphate and gum arabic. Sodium dodecyl sulphate shows higher dispersing effectiveness than gum arabic.

The effect of nickel additions to tune the wear performance of CuZrAl at.% alloy has been studied to present a new strategy for preventing excessive wear rate at high loads in metallic glass composites. This strategy consists on proper selection of a doping element in controlled concentrations with the ability to decrease the glass transition temperature (T) of the alloy so that the friction temperature during sliding is close to the T. This enables the formation of crystalline phases and their subsequent oxidation (lubricating layer) on the contact surface during sliding thus enhancing the wear resistance. Proper doping can also contribute towards the wear resistance when the content of the doping element promotes the martensitic transformation. The results show that the main wear mechanism for the three studied alloys (CuZrAl, CuZrAlNi and CuZrAlNi at.%) is governed by delamination and the mass loss increases with increasing load from 1 to 10 N. However, for the maximum load of 15 N, the calculated friction temperature is close to T for the Ni-containing alloys and partial crystallization and oxidation take place resulting in a mass loss decrease from about 2.6 mg (at 10 N) to about 2.1 mg (at 15 N)., SG is grateful to the Royal Society for the grant RG2015R2. V.M.V. and S.G. acknowledge research support from Northumbria University. Partial financial support from RG2015R2 is acknowledged. J. Medina and P. Pérez would like to acknowledge the expert support of A. García and A. Tomás for assistance with SEM/TEM observations.

Novelty of presented research is focused on ablation and thermomechanical characteristics of various loadings of carbon nanofibers (CNFs) of polyisoprene elastomer (PR). Conventional method (banbury disperser with open mixing mill) is applied to complete fabrication process of CNF-reinforced elastomeric nanocomposites. Scanning electron micrographs confirm the proper distribution of CNFs within the elastomeric host matrix. The successful incorporation of CNFs into PR has reduced the back-face temperature and increased the ablation resistance CNF/PR elastomeric nanocomposite in front of ultrahigh temperature (oxyacetylene flame exposure). Carbon nanofiber network with the elastomeric chain restricts the thermal transport within the CNF/PR nanocomposite specimens. The synergistic effect of CNFs on crystallization, glass transition, melting temperatures (T m) of PR elastomeric nanocomposites is studied. Mechanical properties of PR are effectively enhanced by the impregnation of CNFs in the elastomeric nanocomposites.

Graphene nanosheets (GNS) reinforced Al2O3 nanocomposites were prepared by a rapid sintering route. The microhardness and fracture toughness values of the resulting nanocomposites simultaneously increased due to efficient graphene nanosheet incorporation and chemical interaction with the Al2O3 matrix grains. The properties enhancement is attributed to uniformly dispersed graphene nanosheet in the consolidated structure promoted by high surface roughness and ability of graphene nanosheet to decorate Al2O3 nanoparticles, strong GNS/Al2O3 chemical interaction during colloidal mixing and pullout/crack bridging toughening mechanisms during mechanical testing. The GNS/Al2O3 interaction during different processing stages was thoroughly examined by thermal and structural investigation of the interfacial area. We report formation of an intermediate aluminum oxycarbide phase via a confined carbothermal reduction reaction at the GNS/Al2O3 interface. The graphene nanosheet surface roughness improves GNS/Al2O3 mechanical attachment and chemical compatibility. The Al2O3/GNS interface phase facilitates efficient load transfer, thus delaying failure through impediment of crack propagation. The resulting nanocomposites, therefore, offer superior toughness.

The availability of carbyne in carbon nanotubes (CNTs) induces intrinsic stiffening and strengthening of CNTs, and is exploited for the very first time in this report to process epoxy nanocomposites with improved mechanical and electrical properties. The existence of encapsulated carbyne in double wall CNTs (DWNTs) was confirmed using High Resolution Transmission Electron Microscopy (HR-TEM). The intrinsic stiffening of carbyne reinforced DWNTs (c-DWNTs) in epoxy matrix was visually confirmed by Field Emission Scanning Electron Microscopy (FE-SEM). In comparison to raw DWNTs reinforced epoxy nanocomposites, c-DWNTS imparted modest but improved tensile strength (5.6%), elastic modulus (9.7%), failure strain (9.9%) and fracture toughness (13%) to their respective epoxy nanocomposites. This inaugural study on carbyne-filled polymer composites also reports a minor but distinct increase (an order of magnitude) in the electrical conductivity for c-DWNTs filled epoxy nanocomposites compared to DWNT filled epoxy nanocomposites.

Nanocomposites reinforced with polymer–clay often show dramatic improvements in strength, modulus, thermal resistance and gas permeability at lower clay content than conventional filled polymer composites. This paper focuses on most recent studies of the mechanical properties of nanocomposites with polymer–clay. The improvement of mechanisms in the mechanical properties of nanocomposites with polymer–clay is also discussed.

A novel tweakable nanocomposite was prepared by spark plasma sintering followed by systematic oxidation of carbon nanotube (CNT) molecules to produce alumina/carbon nanotube nanocomposites with surface porosities. The mechanical properties (flexural strength and fracture toughness), surface area, and electrical conductivities were characterized and compared. The nanocomposites were extensively analyzed by field emission scanning electron microscopy (FE-SEM) for 2D qualitative surface morphological analysis. Adding CNTs in ceramic matrices and then systematically oxidizing them, without substantial reduction in densification, induces significant capability to achieve desirable/application oriented balance between mechanical, electrical, and catalytic properties of these ceramic nanocomposites. This novel strategy, upon further development, opens new level of opportunities for real-world/industrial applications of these relatively novel engineering materials.

In this research, solution casting technique was applied to produce four types of nanocomposites. Different ethanol dosages; 0g, 1g, 3g, and 5g were used to disperse graphene in the epoxy matrix. It was observed that 1g dosage of ethanol was the most effective concentration to disperse 1wt% graphene in the epoxy matrix. At 1 g dosage of ethanol used, the Young’s modulus, tensile strength, and toughness were increased by 130%, 76%, and 187% respectively. SEM images illustrated that the graphene was able to inhibit the advancing cracks and detoured cracks propagation. It is observed that the ethanol needs to be removed completely during processing to ensure its effectiveness, otherwise, the remaining ethanol can cause porosity which is undesirable to the tensile properties of the nanocomposites.

This paper details experimental results when turning Ti-6Al-4V using water-miscible vegetable oil-based cutting fluid. The effects of coolant concentration and working conditions on tool flank wear and tool life were evaluated. L27 fractional factorial Taguchi array was employed. Tool wear (VBB) ranged between 28.8 and 110 µm. The study concluded that a combination of VOs based cutting fluid concentration (10%), low cutting speed (58 m/min), feed rate (0.1mm/rev) and depth of cut (0.75mm) is necessary to minimise VBB. Additionally, it is noted that tool wear was significantly affected by cutting speeds. ANOVA results showed that the cutting fluid concentration is statistically insignificant on tool flank wear. A notable increase in tool life (TL) was recorded when a lower cutting speed was used.

The environmental stress cracking resistance of halloysite nanoclay-polyester nanocomposites was investigated using fracture mechanics approach. The incorporation of halloysite nanoclay was found to improve the environmental stress cracking resistance of the nano-composites. The storage modulus of nano-composites measured by dynamic mechanical analysis increased remarkably as a function of halloysite nanoclay content. At 0.7 wt% nanoclay, the Tg improved from 72°C to 76°C. The fracture toughness increased up to 33% and time to failure improved 155% with the addition of 0.7 wt% of halloysite nanoclay. The maximum microhardness was found 119% higher for the same nano-filler concentration compared to monolithic polyester. The reinforcement with 1 wt% showed lower fracture toughness due to agglomerations of nanoclay which act as flaws. The presence of agglomerates weakened the bond between nano-particles and matrix hence reduces the environmental stress cracking resistance by halloysite nanoclay reinforcement.

The topographical features of fractured tensile, flexural, K1C, and impact specimens of 1.0 wt% multi-layered graphene/nanoclay-epoxy nanocomposites have been investigated. The topographical features studied include maximum roughness height ( Rmax or Rz), root mean square value ( Rq), roughness average ( Ra), and waviness ( Wa). Due to deflection and bifurcation of the cracks by nanofillers, specific fracture patterns are observed. Although these fracture patterns seem aesthetically appealing, however, if delved deeper, they can further be used to estimate the influence of nanofiller on the mechanical properties. By a meticulous examination of topographical features of fractured patterns, various important aspects related to fillers can be approximated such as dispersion state, interfacial interactions, presence of agglomerates, and overall influence of the incorporation of filler on the mechanical properties of nanocomposites. In addition, treating the nanocomposites with surfaces of specific topography can help improve the mechanical properties of nanocomposites.

Influence of topography on the variation in mechanical performance of 1.0 wt% multi-layer graphene (MLG)/nanoclay-epoxy samples has been investigated. Three different systems were produced: 1.0 wt% MLG-EP, 1.0 wt% nanoclay-EP, and 0.5 wt% MLG-0.5 wt% nanoclay-EP. The influence of synergistic effect on mechanical performance in case of hybrid nanocomposites is also studied. Various topography parameters studied include maximum roughness height (Rz or Rmax), root mean square value (Rq), roughness average (Ra), and surface waviness (Wa). The Rz of as-cast 1.0 wt% multi-layer graphene, nanoclay, and 0.5 wt% MLG-0.5 wt% nanoclay-EP nanocomposites were 41.43 µm, 43.54 µm, and 40.28 µm, respectively. The 1200P abrasive paper and the velvet cloth decreased the Rz value of samples compared with as-cast samples. In contrary, the 60P and 320 P abrasive papers increased the Rz values. Due to the removal of material from the samples by erosion, the dimensions of samples decreased. The weight loss due to erosion was commensurate with the coarseness of abrasive papers. It was recorded that multi-layer graphene is more influential in enhancing the mechanical performance of epoxy nanocomposites than nanoclay. Additionally, it was observed that mechanical performance of hybrid nanocomposites did not show a marked difference suggesting that synergistic effects are not strong enough in multi-layer graphene and nanoclay.

One of the main issues in the production of polymer nanocomposites is the dispersion state of filler as multilayered graphene (MLG) and carbon nanotubes (CNTs) tend to agglomerate due to van der Waals forces. The agglomeration can be avoided by using organic solvents, selecting suitable dispersion and production methods, and functionalizing the fillers. Another proposed method is the use of hybrid fillers as synergistic effects can cause an improvement in the dispersion state of the fillers. In this review article, various aspects of each process that can help avoid filler agglomeration and improve dispersion state are discussed in detail. This review article would be helpful for both current and prospective researchers in the field of MLG- and CNT-based polymer nanocomposites to achieve maximum enhancement in mechanical, thermal, and electrical properties of produced polymer nanocomposites.

The influence of multi-layered nanostructured graphene as reinforcement on thermal and mechanical properties of epoxy-based nanocomposites has been studied. The maximum improvement in mechanical properties was observed at 0.1 wt%. The Young’s and flexural moduli increased from 610 MPa to 766 MPa (26% increase) and 598.3 MPa to 732.8 MPa (23% increase), respectively. The tensile and flexural strengths increased from 46 MPa to 65 MPa (43% increase) and 74 MPa to 111 MPa (49% increase), respectively. The mode-1 fracture toughness (K1C) and critical strain energy release rate (G1C) increased from 0.85 MPa.m1/2 to 1.2 MPa.m1/2 (41% increase) and from 631 J/m2 to 685 J/m2 (9% increase), respectively. The increase in fracture toughness is attributed to the obstruction of cracks by graphene layers. The reinforcing effect of nanostructured graphene was also manifested in dynamic mechanical properties. The storage modulus and alpha-relaxation temperature values significantly increased indicating the fine integration of NSG in epoxy chains. The thermal properties of nanocomposites were simulated which showed that graphene is very efficient in significantly increasing the scattering and dissipation of thermal flux.

The topographical features of fractured tensile, flexural, K1C, and impact specimens of0.5 wt% multi-layer graphene (MLG)/nanoclay-epoxy (EP) nanocomposites have been investigated.The topographical features studied include maximum roughness height (Rmax or Rz),root meansquare value (Rq), roughness average (Ra), and waviness (Wa).Due to the deflection and bifurcationof cracks by nano-fillers, specific fracture patterns are observed. Although these fracture patternsseem aesthetically appealing, however, if delved deeper, they can further be used to estimate theinfluence of nano-filler on the mechanical properties. By a meticulous examination of topographicalfeatures of fractured patterns, various important aspects related to fillers can be approximated such asdispersion state, interfacial interactions, presence of agglomerates, and overall influence of theincorporation of filler on the mechanical properties of nanocomposites. In addition, treating thenanocomposites with surfaces of specific topography can help improve the mechanical properties ofnanocomposites.

Multi-layered graphene (MLG)–epoxy nanocomposites of three different types were produced using the solution casting technique with MLG dispersed in three different mediums; acetone (MA), an epoxy (ME), and a hardener (MH). In the case of MLG dispersed in the hardener (MH), the maximum increases in tensile and flexural properties, fracture toughness, and microhardness were observed at 0.3 wt% of MLG. The Young's modulus increased from 610 MPa to 758 MPa (24% increase) and the tensile strength increased from 46 MPa to 60 MPa (31% increase). The fracture toughness (K1C) increased from 0.8 MPa m1/2 to 1.1 MPa m1/2 (29% increase) and the Charpy impact toughness increased from 0.85 kJ m−2 to 1.61 kJ m−2 (89% increase). An increase in the storage modulus and glass transition temperature (Tg) was also observed which is attributed to the high stiffness and restriction of polymer chains. Also, if the acetone is not completely removed, the products would have porosity which acts as a stress concentrator and significantly degrades the mechanical properties of the nanocomposites.

Influence of topographical features on mechanical properties of monolithic epoxy samples has been studied. The topographical features studied include waviness (Wa), roughness average (Ra), root mean square value (Rq), and maximum roughness height (Rmax or Rz). The Rz of as-cast monolithic epoxy samples was 13.93 μm. By treating with velvet cloth, the Rz value significantly decreased to 2.28 μm. The Rz value of monolithic epoxy sample treated with abrasive paper 1200P was 4.85 μm which was also lower than that of as-cast monolithic epoxy samples. However, Rz values significantly increased by treating with abrasive papers 320P and 60P and became 20.32 μm and 39.32 μm, respectively. It was interesting to note that although Ra, Wa, and Rq, all increased by treating the monolithic epoxy samples with abrasive paper 1200P, however, Rz decreased by abrasive paper 1200P. A weight loss of up to 17% was observed in monolithic epoxy samples after the treatment with the abrasive papers. Both V-shaped and U-shaped notches were produced on the surfaces of the samples. The mechanical properties were significantly degraded due to surface notches mainly because of the associated stress concentration effect. The topographical features also influenced the dynamic mechanical properties and fracture mode.

Influence of topography on the variation in mechanical performance of 0.5 wt% multi-layer graphene (MLG)/nanoclay-epoxy nanocomposites has been studied. Three different systems were produced: 0.5 wt% MLG-EP, 0.5 wt% nanoclay-EP, and 0.25 wt% MLG-0.25 wt% nanoclay-EP. The influence of synergistic effect on mechanical performance in case of hybrid nanocomposites is also studied. Various topography parameters studied include maximum roughness height (Rz or Rmax),root mean square value (Rq),roughness average (Ra), and surface waviness (Wa).The Rz of as-cast 0.5 wt% MLG, nanoclay, and 0.25 wt% MLG-0.25 wt% nanoclay-EP nanocomposites were 41.43 μm, 43.54 μm, and 40.28 μm, respectively. The 1200P abrasive paper and the velvet cloth decreased the Rzvalue of samples compared with as-cast samples. In contrary, the 60P and 320P abrasive papers increased the Rz values. Due to the removal of material from the samples by erosion, the dimensions of samples decreased. The weight loss due to erosion was commensurate with the coarseness of abrasive papers. It was observed that MLG is more influential in enhancing the mechanical performance of epoxy nanocomposites than nanoclay. In addition, it was observed that mechanical performance of hybrid nanocomposites did not show a marked difference suggesting that synergistic effects are not strong enough in MLG and nanoclay.

Modeling and simulation allow methodical variation of material properties beyond the capacity of experimental methods. Due to the hexagonal structure of graphene, it is considered as frame-like structure. In the frame, covalent C-C bonds are taken as beams joined together with carbon atoms placed at the joints. Uniaxial beam elements, defined by their cross-sectional area, material properties, and moment of inertia represent the covalent bonds. The parameters of the beam elements are determined by establishing equivalence between structural and computational mechanics. However, the bonds connecting the carbon atoms do not have physical existence as they are a compromise between attractive and repulsive forces. Also, defects at nanoscale make graphene different from frame-like structure. In addition, the topography of graphene makes it non-linear structure and even the axial loading changes to eccentric loading. Here we show that, by using basic statics principles, disparities between graphene and frame-likes structures can be highlighted.

Modeling and simulation allow methodical variation of material properties beyond the capacity of experimental methods. The polymers are one of the most commonly used matrices of choice for composites and have found applications in numerous fields. The stiff and fragile structure of monolithic polymers leads to the innate cracks to cause fracture and therefore the engineering applications of monolithic polymers, requiring robust damage tolerance and high fracture toughness, are not ubiquitous. In addition, when “many-parts” cling together to form polymers, a labyrinth of molecules results, which does not offer to electrons and phonons a smooth and continuous passageway. Therefore, the monolithic polymers are bad conductors of heat and electricity. However, it is well established that when polymers are embedded with suitable entities especially nano-fillers, such as metallic oxides, clays, carbon nanotubes, and other carbonaceous materials, their performance is propitiously improved. Among various additives, graphene has recently been employed as nano-filler to enhance mechanical, thermal, electrical, and functional properties of polymers. In this review, advances in the modeling and simulation of grapheme based polymer nanocomposites will be discussed in terms of graphene structure, topographical features, interfacial interactions, dispersion state, aspect ratio, weight fraction, and trade-off between variables and overall performance.

Carbon nanotubes (CNTs) offer the potential for radical transformation of future electronics as they exhibit conductivity, semiconductor and mechanical properties that far exceed those of traditional materials. They thus offer wide opportunities for novel computing devices, especially those required to be small and light, such as “wearables”. They also offer environmental advantages by reducing energy demand in manufacture and use. A practical investigation is reported, focusing on microwave processing of a CNT composite sample. A significant reduction in energy consumption in manufacture while increasing mechanical and electrical performance is deduced, suitable for low power wearable, wireless computing devices. However, CNTs inherently suffer from flaws such as the tendency for nanoparticle agglomerations to form due to strong covalent bonds, and other uncertainties in nanoparticle behaviour. This experimental study demonstrates that microwave processing of CNT composites can reduce the power consumption and the temperature generated during the manufacturing process.

This paper presents static behaviour of functionally graded (FG) sandwich beams by using a quasi-3D theory, which includes both shear deformation and thickness stretching effects. Various symmetric and non-symmetric sandwich beams with FG material in the core or skins under the uniformly distributed load are considered. Finite element model (FEM) and Navier solutions are developed to determine the displacement and stresses of FG sandwich beams for various power-law index, skin-core-skin thickness ratios and boundary conditions. Numerical results are compared with those predicted by other theories to show the effects of shear deformation and thickness stretching on displacement and stresses.

Graphene has recently attracted significant academic and industrial interest because of its excellent performance in mechanical, electrical and thermal applications. Graphene can significantly improve physical properties of epoxy at extremely small loading when incorporated appropriately. Herein, the structure, preparation and properties of epoxy/graphene nanocomposites are reviewed in general, along with detailed examples drawn from the key scientific literature. The modification of graphene and the utilization of these materials in the fabrication of nanocomposites with different processing methods have been explored. This review has been focused on the processing methods and mechanical, electrical, thermal, and fire retardant properties of the nanocomposites. The synergic effects of graphene and other fillers in epoxy matrix have been summarised as well.

It is generally recognized that dimethylformamide (DMF) and ethanol are good media to uniformly disperse graphene, and therefore have been used widely in the preparation of epoxy/graphene nanocomposites. However, as a solvent to disperse graphene, dichlorobenzene (DCB) has not been fully realized by the polymer community. Owing to high values of the dispersion component ( δ d ) of the Hildebrand solubility parameter, DCB is considered as a suitable solvent for homogeneous graphene dispersion. Therefore, epoxy/graphene nanocomposites have been prepared for the first time with DCB as a dispersant; DMF and ethanol have been chosen as the reference. The colloidal stability, mechanical properties, thermogravimetric analysis, dynamic mechanical analysis and scanning electron microscopic images of nanocomposites have been obtained. The results show that with the use of DCB, the tensile strength of graphene has been improved from 64.46 to 69.32 MPa, and its flexural strength has been increased from 97.17 to 104.77 MPa. DCB is found to be more effective than DMF and ethanol for making stable and homogeneous graphene dispersion and composites.

A controlled cutting fluid impinging supply system (CUT-LIST) was developed to deliver an accurate amount of cutting fluid into the machining zone via well-positioned coherent nozzles based on a calculation of the heat generated. The performance of the CUT-LIST was evaluated against a conventional flood cutting fluid supply system during step shoulder milling of Ti-6Al-4V using vegetable oil-based cutting fluid. In this paper, the micro-hardness of the machined surface was used as the main criterion to compare the two systems. CUT-LIST provided significant reductions in cutting fluid consumption (up to 42%). Both systems caused increased micro-hardness value at 100 µm from the machined surface, whereas a slight reduction in micro-hardness of 4.5% was measured when using CUL-LIST. It was noted that the first 50 µm is the soft sub-surface promoted by thermal softening, whereas down to 100 µm is the hard sub-surface caused by the cyclic internal work hardening and then gradually decreased until it reached the base material nominal hardness. It can be concluded that the CUT-LIST has always given lower micro-hardness values near the machined surfaces in all conditions investigated., {"references":["El Baradie, M.A., Cutting fluids: Part I. Characterisation. Journal of Materials Processing Technology, 1996. 56(1–4): p. 786-797.","Sharma, A.K., A.K. Tiwari, and A.R. Dixit, Effects of Minimum Quantity Lubrication (MQL) in machining processes using conventional and nanofluid based cutting fluids: A comprehensive review. Journal of Cleaner Production, 2016. 127: p. 1-18.","Veiga, C., J. Davim, and A. Loureiro, Review on machinability of titanium alloys: the process perspective. Reviews on Advanced Materials Science, 2013. 34(2): p. 148-164.","Ezugwu, E.O., J. Bonney, and Y. Yamane, An overview of the machinability of aeroengine alloys. Journal of Materials Processing Technology, 2003. 134(2): p. 233-253.","S. A. Lawal, I.A.C., I. Q. Sadiq and A. Oyewole, Vegetable-oil based metalworking fluids research developments for machining processes: survey, applications and challenges. 2014, Manufacturing Review.","Srikant, R.R. and V.S.N.V. Ramana, Performance evaluation of vegetable emulsifier based green cutting fluid in turning of American Iron and Steel Institute (AISI) 1040 steel – an initiative towards sustainable manufacturing. Journal of Cleaner Production.","Kuram, E., B. Ozcelik, and E. Demirbas, Environmentally friendly machining: vegetable based cutting fluids, in Green Manufacturing Processes and Systems. 2013, Springer. p. 23-47.","Debnath, S., M.M. Reddy, and Q.S. Yi, Environmental friendly cutting fluids and cooling techniques in machining: a review. Journal of Cleaner Production, 2014. 83(0): p. 33-47.","Jayal, A.D. and A.K. Balaji, Effects of cutting fluid application on tool wear in machining: Interactions with tool-coatings and tool surface features. Wear, 2009. 267(9–10): p. 1723-1730.\n[10]\tBabic, D., D.B. Murray, and A.A. Torrance, Mist jet cooling of grinding processes. International Journal of Machine Tools and Manufacture, 2005. 45(10): p. 1171-1177.\n[11]\tGinting, A. and M. Nouari, Surface integrity of dry machined titanium alloys. International Journal of Machine Tools and Manufacture, 2009. 49(3–4): p. 325-332.\n[12]\tEzugwu, E.O., et al., Surface integrity of finished turned Ti–6Al–4V alloy with PCD tools using conventional and high pressure coolant supplies. International Journal of Machine Tools and Manufacture, 2007. 47(6): p. 884-891.\n[13]\tAntonialli, A.Í.S., A.E. Diniz, and H.K. Neto, Tool Life and Machined Surface Damage on Titanium Alloy Milling Using Different Cooling-Lubrication Conditions. 2009.\n[14]\tDe Angelo Sanchez, L.E., et al., Effect of different methods of cutting fluid application on turning of a difficult-to-machine steel (SAE EV-8). Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 2013. 227(2): p. 220-234.\n[15]\tWebster, J., Improving surface integrity and economics of grinding by optimum coolant application, with consideration of abrasive tool and process regime. Proceedings of the institution of mechanical engineers, Part B: journal of engineering manufacture, 2007. 221(12): p. 1665-1675.\n[16]\tMorgan, M.N. and V. Baines-Jones, On the coherent length of fluid nozzles in grinding. Key Engineering Materials, 2009. 404: p. 61-67.\n[17]\tBoothroyd, G. and W.A. Knight, Fundamental of Machining and Machine Tool. 2005, USA: CRC Press and Francis & Taylor.\n[18]\tDavid A. Stephenson, J.S.A., Metal cutting Theory and Practice. 2005, Taylor & Francis Group. p. 425.\n[19]\tShaw, M.C., in Metal Cutting Principles. 1954, 1957, M.I.T Press Massachusetts Institute of Technology: USA. p. 12-1.\n[20]\tMetzger, J.L., Superabrasive Grinding. 1986, UK: Butterworths. pp134.\n[21]\tLuchesi, V.M. and R.T. Coelho, Experimental investigations of heat transfer coefficients of cutting fluids in metal cutting processes: analysis of workpiece phenomena in a given case study. Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 2012: p. 0954405412442459.\n[22]\tKennametal. Titanium Machining Guide. 2016 (cited 2016 28 April).\n[23]\tWebster, J.A., Coolant Calculus, in Cutting Tool Engineering. 2008, Cutting Tool Engineering: USA. p. 8."]}

Ti-12Mo-6Zr/Al2O3 (titanium biomaterial) was prepared by a powder metallurgy route using Spark Plasma Sintering (SPS). Ti, Mo, and Zr powders were mixed by wet milling with different content of alumina nanoparticles (up to 5 wt pct) as an oxide dispersion strengthening phase. Composite powder mixtures were SPSed at 1273 K (1000 °C) followed by heat treatment and quenching. Composite powders, sintered materials, and heat-treated materials were examined using optical and high-resolution electronic microscopy (scanning and transmission) and X-ray diffraction to characterize particle size, surface morphology, and phase identifications for each composition. All sintered materials were evaluated by measuring density, Vickers hardness, and tensile properties. Fully dense sintered materials were produced by SPS and mechanical properties were found to be improved by subsequent heat treatment. The tensile properties as well as the hardness were increased by increasing the content of Al2O3 nanoparticles in the Ti-12Mo-6Zr matrix.

The post-sintering structural stability of graphene in alumina nanocomposites synthesised by Spark Plasma Sintering (SPS) and Hot Pressing (HP) was compared. Raman spectroscopy, thermogravimetric analyses and electrical conductivity analyses were conducted to characterise degradation of graphene due to the utilisation of different sintering techniques and conditions. Scanning Electron Microscopy confirmed good dispersion of graphene in SPSed and HPed sample. Graphene in SPSed and HPed nanocomposite samples sintered using longer durations (60 min) were found to possess higher crystallinity, thermal stability and electrical conductivity as compared to SPSed samples sintered using shorter sintering durations (10–20 min). This was attributed to the thermally induced graphitisation caused by longer sintering durations, which was lacking in SPSed samples processed using shorter sintering durations and lower temperature. No additional effect of DC pulsed current on the structural stability of graphene for nanocomposites were observed for samples prepared by SPS.

Gum Arabic (GA), Sodium Dodecyl Sulfate (SDS) and their mixture were used for the dispersion of multi-walled carbon nanotubes (CNTs) in an alumina matrix. A good dispersion at low loadings (0.5-1 wt%) of CNTs in alumina was achieved by an ultrasonic bath treatment. Dispersions were evaluated by UV-vis spectroscopy and agglomerate size analysis. The mixture of GA and SDS produced good dispersion as compared to GA and SDS alone. Nanocomposite powders were sintered by Spark Plasma Sintering (SPS). Microstructural, electrical and mechanical characterizations of sintered discs were carried out to evaluate the effectiveness of the different dispersants. The mixture of GA and SDS produced homogeneous and agglomerate-free CNT-alumina nanocomposites with higher electrical conductivity and indentation fracture toughness as compared to nanocomposites prepared using GA and SDS alone.