Microstructural characterization and mechanical properties of(TiC+TiB)/TA15 composites prepared by an in-situ synthesis method

Titanium matrix composites reinforced with ceramic particles are considered a promising engineering material due to their combination of high specific strength,low density,and high modulus.In this study,the TA15-based composites reinforced with a volume fraction of 10% to 25%(TiB+TiC)were prepared using powder metallurgy and casting technique.Microstructural characterization and phase constitution were examined using optical microscopy(OM),scanning electron microscopy(SEM),and X-ray diffraction(XRD).In addition,the microhardness,room temperature(RT)and high temperature(HT)tensile properties of the composites were evaluated.Results revealed that the reinforcements are distributed uniformly even in the composites with a high volume of TiB and TiC.However,as the volume fraction exceeds 15%,TiB and TiC particles become coarsening and exhibit rod-like and dendritic-like morphology.Microhardness increases gradually from 321.2 HV for the base alloy to a maximum of 473.3 HV as the reinforcement increases to 25vol.%.Tensile test results indicate that a reinforcement volume fraction above 20% is beneficial for enhancing tensile strength and yield strength at high temperatures,but it has an adverse effect on room temperature elongation.Conversely,if the reinforcement volume fraction is below 20%,it can improve high-temperature elongation when the temperature exceeds 600℃.

In-situ additive manufacturing of high strength yet ductility titanium composites with gradient layered structure using N_(2)

It has always been challenging work to reconcile the contradiction between the strength and plasticity of titanium materials.Laser powder bed fusion(LPBF) is a convenient method to fabricate innovative composites including those inspired by gradient layered materials.In this work,we used LPBF to selectively prepare Ti N/Ti gradient layered structure(GLSTi)composites by using different N_(2)–Ar ratios during the LPBF process.We systematically investigated the mechanisms of in-situ synthesis Ti N,high strength and ductility of GLSTi composites using microscopic analysis,TEM characterization,and tensile testing with digital image correlation.Besides,a digital correspondence was established between the N_(2) concentration and the volume fraction of LPBF in-situ synthesized Ti N.Our results show that the GLSTi composites exhibit superior mechanical properties compared to pure titanium fabricated by LPBF under pure Ar.Specifically,the tensile strength of GLSTi was more than 1.5times higher than that of LPBF-formed pure titanium,reaching up to 1100 MPa,while maintaining a high elongation at fracture of 17%.GLSTi breaks the bottleneck of high strength but low ductility exhibited by conventional nanoceramic particle-strengthened titanium matrix composites,and the hetero-deformation induced strengthening effect formed by the Ti N/Ti layered structure explained its strength-plasticity balanced principle.The microhardness exhibits a jagged variation of the relatively low hardness of 245 HV0.2 for the pure titanium layer and a high hardness of 408 HV0.2 for the N_(2) in-situ synthesis layer.Our study provides a new concept for the structure-performance digital customization of 3D-printed Ti-based composites.

Composite Panels from the Combination of Rice Husk and Wood Chips with a Natural Resin Based on Tannins Reinforced with Sugar Cane Molasses Intended for Building Insulation: Physico-Mechanical and Thermal Properties

The objective of this work is to develop new biosourced insulating composites from rice husks and wood chips that can be used in the building sector. It appears from the properties of the precursors that rice chips and husks are materials which can have good thermal conductivity and therefore the combination of these precursors could make it possible to obtain panels with good insulating properties. With regard to environmental and climatic constraints, the composite panels formulated at various rates were tested and the physico-mechanical and thermal properties showed that it was essential to add a crosslinker in order to increase certain solicitation. an incorporation rate of 12% to 30% made it possible to obtain panels with low thermal conductivity, a low surface water absorption capacity and which gives the composite good thermal insulation and will find many applications in the construction and real estate sector. Finally, new solutions to improve the fire reaction of the insulation panels are tested which allows to identify suitable solutions for the developed composites. In view of the flame tests, the panels obtained are good and can effectively combat fire safety in public buildings.

Investigation into machining performance of microstructurally engineered in-situ particle reinforced magnesium matrix composite

Magnesium and magnesium in-situ composites have significant potential in the application of design and manufacturing for automotive and aerospace industries because of their high specific strength and reduced fuel consumption.But there are many challenges for machining of Mg based alloys and composites because of the high tendency of fire and oxidation.These challenges can be minimized through microstructural engineering.In this present study,the machining performances of AZ91 Mg alloy and in-situ hybrid TiC+TiB_(2)reinforced AZ91 metal matrix composite was investigated.The effectβ-Mg_(17)Al_(12)phases and grain refinement with and without in-situ particles on machinability were studied through microstructural engineering via aging and friction stir processing.The end milling operation was carried out at different cutting speeds ranging from 25 mm/min to 90 mm/min under dry environment by using an AlTiN-coated tungsten carbide tool.The optimum cutting speed for machining was found to be 75 mm/min based on the surface roughness values of all conditioned materials.The base material with dendritic microstructure was found to have poor machinability in terms of inadequate surface finish and edge-burrs formation.The combined effect of in-situ TiC+TiB_(2)particles addition and grain refinement enhanced the machining performance of the material with superior surface finish,negligible edge-burr formation and better tool wear resistance.The influence of in-situ TiC+TiB_(2)particles,β-Mg_(17)Al_(12)phases and grain refinement on machining characteristics are explained based on the tool wear mechanisms,chip behavior and machining induced affected zone.

Microwave Absorption and Mechanical Properties of Short-cutted Carbon Fiber/glass Fiber Hybrid Veil Reinforced Epoxy Composites

This work aims at investigating the microwave absorption and mechanical properties of short-cutted carbon fiber/glass fiber hybrid veil reinforced epoxy composites.The short-cutted carbon fibers(CFs)/glass fibers(GFs)hybrid veil were prepared by papermaking technology,and composites liquid molding was employed to manufacture CFs/GFs hybrid epoxy composites.The microstructure,microwave absorbing properties and mechanical properties of the hybrid epoxy composites were studied by using SEM,vector network analyzer and universal material testing,respectively.The reflection coefficient of the composites were calculated by the measured complex permittivity and permeability in the X-band(8.2-12.4 GHz)range.The optimum microwave absorption properties can be obtained when the content of CFs in the hybrid veil is 6 wt%and the thickness of the composites is 2 mm,the minimum reflection coefficient of-31.8 dB and the effective absorption bandwidth is 2.1 GHz,which is ascribed to benefitting impedance matching characteristic and dielectric loss of the carbon fiber.Simultaneously the tensile strength and modulus can achieve 104.0 and 2.98GPa,demonstrating that the CFs/GFs hybrid epoxy composites can be a promising candidate of microwave absorbing materials with high mechanical properties.

Multiphysics processes in the interfacial transition zone of fiber-reinforced cementitious composites under induced curing pressure and implications for mine backfill materials: A critical review

The mesoscale fiber-matrix interfacial transition zone(FM-ITZ) under induced curing pressure plays a key role in the effectiveness of fiber reinforcement and the engineering application of fiber-reinforced cementitious composites(FRCCs). This critical review establishes the link among induced curing pressure(i.e., external loading condition), multiphysics processes(i.e., internal governing mechanism), and interface behavior(i.e., material behavior) for FRCC materials through analysis of the state-of-the-art research findings on the FM-ITZ of FRCC materials. The following results are obtained. For the mechanical process, the induced curing pressure changes the stress state and enhances multicracking behavior, which can strengthen the FM-ITZ. For the hydraulic process, the strengthened seepage of the FM-ITZ under induced curing pressure weakens the effective stress and exaggerates the deficiency in water retention capacity between the bulk matrix and the FMITZ. For the thermal process, the induced curing pressure causes a steep temperature gradient in the FM-ITZ and thus influences the temperature evolution and thermally-induced microcracks in the FM-ITZ. For the chemical process, the induced curing pressure enhances hydration kinetics and results in the formation of additional hydration products in the FM-ITZ. Moreover, recommendations are proposed on the basis of findings from this review to facilitate the implementation of fiber reinforcement in cemented paste backfill technology.

Preparation and Investigation of Mechanical and Physical Properties of Flax/Glass Fabric Reinforced Polymer Hybrid Composites

Synthetic reinforced composites affect the environment adversely and have become a global concern, causing increased natural composite demand for sustainability and cost effectiveness. Glass is a popular material that is highly consumed in reinforced composites for its superior mechanical strength. As opposed to that, flax obtained from flax stalks can be used as an alternative reinforcing material with synthetic fibers to minimize manmade fiber consumption. Hence, this research work addresses a few flax/glass-reinforced hybrid composites by using a thermoset polyester matrix. Here, six categories of samples are made, like neat flax, neat glass, and flax/glass fabric reinforced hybrid composite, followed by different stacking layer sequences and hand layout techniques during processing. Afterwards, the mechanical behavior, thermal stability, morphological behavior, and water absorption of hybrid samples were investigated. Among the developed samples, neat glass (NG) composite exhibits superior mechanical properties, while neat flax (NF) shows the lowest result. It is apparent that the mechanical properties and thermal stability of hybrid samples are in between NF and NG because, by adding glass with flax fabric, the strength of hybrid samples is increased. Moreover, it is noticeable that, due to multiple stacking layers of flax and glass, hybrid 3 and hybrid 4 show better strength than consecutive single stacking layers in hybrid 1 and hybrid 2. Among all hybrid composites, the H4 shows comparatively better mechanical and thermal properties due to having the glass layers on the outermost surface. In summary, this research work demonstrated the feasibility of flax fabric with glass fabric as a reinforced hybrid composite that can be used in automobile inner bodies, household furnishing, and home interior decoration.

Preparation and Investigation of Mechanical and Physical Properties of Flax/Glass Fabric Reinforced Polymer Hybrid Composites

Synthetic reinforced composites affect the environment adversely and have become a global concern, causing increased natural composite demand for sustainability and cost effectiveness. Glass is a popular material that is highly consumed in reinforced composites for its superior mechanical strength. As opposed to that, flax obtained from flax stalks can be used as an alternative reinforcing material with synthetic fibers to minimize manmade fiber consumption. Hence, this research work addresses a few flax/glass-reinforced hybrid composites by using a thermoset polyester matrix. Here, six categories of samples are made, like neat flax, neat glass, and flax/glass fabric reinforced hybrid composite, followed by different stacking layer sequences and hand layout techniques during processing. Afterwards, the mechanical behavior, thermal stability, morphological behavior, and water absorption of hybrid samples were investigated. Among the developed samples, neat glass (NG) composite exhibits superior mechanical properties, while neat flax (NF) shows the lowest result. It is apparent that the mechanical properties and thermal stability of hybrid samples are in between NF and NG because, by adding glass with flax fabric, the strength of hybrid samples is increased. Moreover, it is noticeable that, due to multiple stacking layers of flax and glass, hybrid 3 and hybrid 4 show better strength than consecutive single stacking layers in hybrid 1 and hybrid 2. Among all hybrid composites, the H4 shows comparatively better mechanical and thermal properties due to having the glass layers on the outermost surface. In summary, this research work demonstrated the feasibility of flax fabric with glass fabric as a reinforced hybrid composite that can be used in automobile inner bodies, household furnishing, and home interior decoration.

Effect of Silane Coupling Agent Concentration on Interfacial Properties of Basalt Fiber Reinforced Composites

The purpose of this study is to investigate the effect of the concentration of silane coupling solution on the tensile strength of basalt fiber and the interfacial properties of basalt fiber reinforced polymer composites.The surface treatment of basalt fibers was carried out using an aqueous alcohol solution method.Basalt fibers were subjected to surface treatment with 3-Methacryloxypropyl trimethoxy silane at 0.5 wt.%,1 wt.%,2 wt.%,4 wt.%and 10 wt.%.The basalt monofilament tensile tests were carried out to investigate the variation in strength with the concentration of the silane coupling agent.The microdroplet test was performed to examine the effect of the concentration of the silane coupling agent on interfacial strength of basalt reinforced polymer composites.The film was formed on the surface of the basalt fiber treated silane coupling agent solution.The tensile strength of basalt fiber increased because the damaged fiber surface was repaired by the firm of silane coupling agent.The firm was effective in not only the surface protection of basalt fiber but also the improvement on the interfacial strength of fiber-matrix interface.However,the surface treatment using the high concentration silane coupling agent solution has an adverse effect on the mechanical properties of the composite materials,because of causing the degradation of the interfacial strength of the composite materials.

In-situ fabrication of particulate reinforced aluminum matrix composites under high-frequency pulsed electromagnetic field

Pulsed magnetic field is generated when imposing pulse signal on high-frequency magnetic field. Distribution of the inner magnetic intensity in induction coils tends to be uniform. Furthermore oscillation and disturbance phenomena appear in the melt. In. situ Al2O3 and Al3Zr particulate reinforced aluminum matrix composites have been synthesized by direct melt reaction using AlZr（CO3）2 components under a foreign field. The size of reinforced particulates is 2-3 μm. They are well distributed in the matrix. Thermodynamic and kinetic analysis show that high-frequency pulsed magnetic field accelerates heat and mass transfer processes and improves the kinetic condition of in-situ fabrication.

PARTICLES ANALYSIS OF Al_2O_3 PARTICLE REINFORCED ZL202 MATRIX COMPOSITES PREPARED BY IN-SITU REACTION

ZL202 matrix composite reinforced by Al2O3 particles was prepared by combining in-situ reaction and casting techniques. Particles' size in the composites was from 1 to 5 microns in diameter. X-ray diffraction analysis verified that the reinforcing particleswere δ-Al2O3 which belong to γ-Al2O3 series. The wetting angle between matrix andreinforcement was less than 90°. Energy spectrum analysis indicated that the reactionin bell cover pressing process took place not so completely as in flouring stir process. When the reaction was finished, the matrix was still ZL202 alloy in both.processes.

A Comparative Study on the Post-Buckling Behavior of Reinforced Thermoplastic Pipes(RTPs)Under External Pressure Considering Progressive Failure

The collapse pressure is a key parameter when RTPs are applied in harsh deep-water environments.To investigate the collapse of RTPs,numerical simulations and hydrostatic pressure tests are conducted.For the numerical simulations,the eigenvalue analysis and Riks analysis are combined,in which the Hashin failure criterion and fracture energy stiffness degradation model are used to simulate the progressive failure of composites,and the“infinite”boundary conditions are applied to eliminate the boundary effects.As for the hydrostatic pressure tests,RTP specimens were placed in a hydrostatic chamber after filled with water.It has been observed that the cross-section of the middle part collapses when it reaches the maximum pressure.The collapse pressure obtained from the numerical simulations agrees well with that in the experiment.Meanwhile,the applicability of NASA SP-8007 formula on the collapse pressure prediction was also discussed.It has a relatively greater difference because of the ignorance of the progressive failure of composites.For the parametric study,it is found that RTPs have much higher first-ply-failure pressure when the winding angles are between 50°and 70°.Besides,the effect of debonding and initial ovality,and the contribution of the liner and coating are also discussed.

Microstructural characterization,tribological and corrosion behavior of AA7075-TiC composites

Aluminum alloys are the potential materials in the automobile and aerospace sectors due to their lower density,easy forming and excellent corrosion resistance.The demand of high strength-to-weight ratio materials in structural applications needs the engineering industries to seek aluminum alloy with new versions of hard and brittle ceramic particles.The microstructure,hardness,wear and corrosion behaviors of AA7075 composites with 2.5wt.%and 5wt.%TiC particles were studied.Microscopic analysis is evident that the transformation of the strong dendritic morphology to non-dendritic morphology on the incorporation of TiC into AA7075.Furthermore,the precipitation of the second-phase compounds such as Al_(2)CuMg,Al_(2)Cu andFe-rich Al_6(Cu,Fe)/Al_(7)Cu_(2)Fe)is promoted by TiC particles at inter-and intra-dendritic regions.Accordingly,the hardness of composites is improved by grain boundary strengthening and particulate strengthening mechanisms.Both coefficient of friction and wear rate have an inverse relation with TiC concentration.The base alloy without TiC shows adhesive-type wear-induced deformation due to the formation of an oxide film,while composite samples exhibit a mechanically mixed layer and abrasive-type wear behavior.Composite samples shows a higher corrosion rate due to the presence of numerous precipitates which promote pitting corrosion.

Optimization Mechanism of Mechanical Properties of Basalt Fiber-Epoxy Resin Composites by Interfacially Enriched Distribution of Nano-Starch Crystals

Fibre reinforced polymer composites have become a new generation of structural materials due to their unique advantages such as high specific strength,designability,good dimensional stability and ease of large-area monolithic forming.However,the problem of interfacial bonding between the resin matrix and the fibres limits the direct use of reinforcing fibres and has become a central difficulty in the development of basalt fibre-epoxy composites.This paper proposes a solution for enhancing the strength of the fibre-resin interface using maize starch nanocrystals,which are highly yield and eco-friendly.Firstly,in this paper,corn starch nanocrystals(SNC)were prepared by hydrolysis,and were deposited on the surface of basalt fibers by electrostatic adsorption.After that,in order to maximize the modification effect of nano-starch crystals on the interface,the basalt fiber-epoxy resin composite samples were prepared by mixing in a pressureless molding method.The test results shown that the addition of basalt fibers alone led to a reduction in the strength of the sample.Deposition of 0.1 wt%SNC on the surface of basalt fibers can make the strength consistent with pure epoxy resin.When the adsorption amount of SNC reached 0.5 wt%,the tensile strength of the samples was 23.7%higher than that of pure epoxy resin.This is due to the formation of ether bond homopolymers between the SNC at the fibre-epoxy interface and the epoxy resin,which distorts the originally smooth interface,leading to increased stress concentration and the development of cracks.This enhances the binding of basalt fibers.The conclusions of this paper can provide an effective,simple,low-cost and non-polluting method of interfacial enhancement modification.

Sustainable Biocomposites Materials for Automotive Brake Pad Application:An Overview

Research into converting waste into viable eco-friendly products has gained global concern.Using natural fibres and pulverized metallic waste becomes necessary to reduce noxious environmental emissions due to indiscriminately occupying the land.This study reviews the literature in the broad area of green composites in search of materials that can be used in automotive brake pads.Materials made by biocomposite,rather than fossil fuels,will be favoured.A database containing the tribo-mechanical performance of numerous potential components for the future green composite was established using the technical details of bio-polymers and natural reinforcements.The development of materials with diverse compositions and varying proportions is now conceivable,and these materials can be permanently connected in fully regulated processes.This explanation demonstrates that all of these variables affect friction coefficient,resistance to wear from friction and high temperatures,and the operating life of brake pads to varying degrees.In this study,renewable materials for the matrix and reinforcement are screened to determine which have sufficient strength,coefficient of friction,wear resistance properties,and reasonable costs,making them a feasible option for a green composite.The most significant,intriguing,and unusual materials used in manufacturing brake pads are gathered in this review,which also analyzes how they affect the tribological characteristics of the pads.

Characteristic of Fresh and Harden Properties of Polyvinyl Alcohol Fibre Reinforced Alkali Activated Composite

Fibre can enhance the mechanical properties of cement-based composites,but fibre also degrades their workability.However,the quantitative effects of fiber content and length-diameter ratio on alkali-activated materials are still unclear.Various aspect ratio,volume fraction of polyvinyl alcohol fibre(PVAF),and various water-binder ratio were employed to prepare a total of 26 groups of fibre reinforced alkali-activated composite(FRAAC).The influence of PVAF fibre factor(product of fiber volume fraction and length-diameter ratio)on flowability,compactness,strength,and crack fractal dimension of FRAAC was researched.The influence of water-binder ratio on the plastic viscosity of FRAAC was more significant than that on the yield stress.When fibre factor was lower than critical value of 150,the influence of fibres could be overlooked.The reason was that the space between fibres was distant,so the flowability of FRAAC was not impacted by PVAF.At this time,fibres were challenging to restrict the cracks in matrix and increase their mechanical properties.When fibre factor was higher than critical value 150 and lower than density packing value 450,the flexural strength,compressive strength and crack fractal dimension of FRAAC were considerably enhanced,and the FRAAC could still flow easily under dead weight.When fibre factor were above 450,noteworthy fibre balling considerably decreased the flowability,leading to poor solidity and reduced compressive strength.Hence,the ideal content of PVAF in alkali activated composite is between 150/(l/d)and 450/(l/d).

The properties of flax fiber reinforced wood flour/high density polyethylene composites

Flax fiber(FF) was used to reinforce wood flour/high density polyethylene composites(WF/PE).WF/PE particles were uniformly mixed with FF via high-speed mixing and then extruded with a single screw extruder to prepare FF reinforced WF/PE composites(FF/WF/PE).Mechanical testing,dynamic mechanical analysis,scanning electron microscopy(SEM),creep measurement and Torque rheology were used to characterize the resulting composites.The results indicate that the mechanical performance of the composites could be remarkably improved by adding a limited amount of FF.The flexural strength and modulus increased by 14.6 and 51.4%,respectively(FF content of 9 wt%),while the unnotched impact strength could be increased by 26.5%(FF content of12 wt%).The creep resistance and toughness of thecomposite was markedly improved without changing the plastic content of the composite material.

Mechanical Properties of Mo Fiber-reinforced Resin Mineral Composites with Different Mass Ratio of Resin and Hardener

Mo fibers were added to RMC with different mass ratios of resin and hardener to improve its mechanical properties. The influences of fiber surface state and hardener content on interface bonding strength and mechanical properties of RMC were studied, respectively. Furthermore, strain values of typical measuring points on samples of Mo fiber reinforced RMC(MFRRMC) under different loads were obtained by experiments and finite element analysis. The experimental results prove that scrap Mo fibers can improve interface bonding strength and mechanical properties of RMC better than new smooth Mo fibers because of the discharge pits randomly distributed on the surface of scrap fibers. With the decrease of hardener content, not only interface bonding strength between fiber and matrix, but also compression and flexural strength of MFRRMC increase firstly and then decrease. The properties are best while the mass ratio of resin and hardener reaches 4:1. It is indicated that finite element calculation data basically agree with experimental data by comparison of strain values on typical measuring points, which can provide an important intuitive reference for successive study on other mechanical properties of MFRRMC, validating the correctness of simulation method as well.

Diffusion Bonding of Silicon Carbide Particulate Reinforced 2024 Al Composites

A study has been made on diffusion bonding of SiCp/2024Ai composites by means of pure Al interlayer. In the condition of TB=843 K, PB=16 MPa, tB= 60 min, the diffusion bonded joint, with a shear strength of 235 MPa, was obtained when a 15 μm thick interlayer was used. The results of the shear testing and SEM indicate that fracture of the joint presented characteristics of ductile rupture.

Resistance welding of carbon fibre reinforced polyetheretherketone composites using metal mesh and PEI film

Weldability of polyetheretherketone(PEEK) with polyetherimide(PEI) is tested. And carbon fiber reinforced PEEK laminates are resistance welded using stainless steel mesh heating element. The effects of the welding time and welding pressure on the lap shear strength of joints are investigated. Results show that PEEK can heal with PEI well in welding condition and the lap shear strength of PEEK/CF(carbon fibre) joint increases linearly with welding time, but reaches a maximum value when welding pressure ranging from 0.3 MPa to 0.5 MPa with constant welding time. The fracture characteristics of surface are analyzed by SEM techniques, and four types of fracture modes of lap shear joints are suggested.