Reinforced Metal Matrix Composites Research Articles

Modeling the temperature-dependent Young’s modulus of short fiber reinforced metal matrix composites and its particle hybrid composites

Modeling the temperature-dependent Young’s modulus of short fiber reinforced metal matrix composites and its particle hybrid composites

Monte carlo based strategy to simulate the microstructure evolution of the short-fiber reinforced metal matrix composites

In this paper, a modified Monte Carlo model considering two types of topological transformations of the grain growth is proposed to simulate the microstructure evolution of short-fiber reinforced metal composites. In the numerical simulation, the representative volume element of the composites is generated by using the Random Sequential Adsorption algorithm. The microstructure evolution and the grain growth kinetics of both the composites and alloy are numerically implemented. By comparing with the experimental tests, the rationality of the proposed model is verified. The results show that the addition of short fibers contributes to the growth and the refinement of matrix alloy grains. Meanwhile, the short-fiber reinforced phase promotes the distribution of the relative grain size of composites more uniform. With the increase of fiber volume fraction, the average grain size of composites decreases, while the equivalent grain size of the composites increases with the increases of the fiber length.

Quasi-continuous GNS network induced local dynamic recrystallization along interfaces in titanium MMCs under high strain rate loading

Despite extensive research on graphene reinforced metal matrix composites (MMCs) over the past decade, the microstructure evolution of the composites still remains inexplicable, especially for dynamic loading conditions. The present work adopted a Ti–6Al–4V composite reinforced with quasi-continuous graphene nanosheets (GNSs) networks to investigate the role of reinforcement and its architecture on the mechanical response, microstructure evolution, and failure mechanism at different loading rates via Hopkinson bar system, Raman and X-ray diffraction examination, transmission electron microscope, and electron backscatter diffraction system. The results reveal that GNSs provide a significant strength improvement, owing to the formation of a quasi-continuous network comprising of GNSs and in-situ produced TiC particles. It is also found with microstructural examination that the local deformation is primarily mediated by the matrix, for which abundant local dynamic recrystallization was detected along the network-matrix interface. This may account for the reduced strain rate sensitivity and a propensity for adiabatic shear band (ASB) under impact loading for the composites. The mechanism of action of the quasi-continuous GNS network architecture is discussed in terms of the strengthening, strain rate sensitivity and ASB propensity of the composites with a quantative assessment.

Experimental study on laser assisted ultrasonic elliptical vibration turning (LA-UEVT) of 70% SiCp/Al composites

SiCp/Al composites are more and more used in aerospace, military industry and other industries. However, the surface integrity of materials is poor, and the cutting force is large as the anisotropy of materials in the traditional machining (TM) process, which hinders the application of ceramic particle reinforced metal matrix composites. With the requirement of high dimensional accuracy, high efficiency and low damage for materials in these fields, non-traditional machining technology has become a research hotspot. Laser assisted machining (LAM) is a non-contact special machining method. Its advantages in machining SiCp/Al composites have been proved by experiments, but there are still processing defects such as thermal cracks. Therefore, to further improve the machining quality of 70% SiCp/Al composites with high volume fraction, a new machining method combining ultrasonic elliptical vibration turning (UEVT) and laser heating assisted turning (LAT) is proposed. High frequency intermittent machining and the adjustment of laser temperature influence on materials can be realized by adjusting the ultrasonic amplitude. Combining the characteristics of the two processing techniques, the feasibility study of the new machining method was studied by turning experiments. In this paper, compared with TM and LAT, the removal mechanism of materials and the effects of different laser heating temperatures and ultrasonic vibration on cutting force, surface quality, subsurface damage and chip morphology are explored. The results show that LA-UEVT can effectively reduce the cutting force and surface roughness, improve the plastic removal ability, and inhibit surface and subsurface damage. And the material removal process is mainly in the form of small particle crushing and particle pressing, which improves the stability of cutting force in the cutting process.

Nanoscale Detonation Carbon Demonstrates Biosafety in Human Cell Culture

The production method of nanoscale detonation carbon (NDC) has recently been developed at Lavrentyev Institute of Hydrodynamics SB RAS. This method uses the reaction of acetylene with oxygen conducted in the detonation mode in fuel-rich acetylene–oxygen mixtures. The morphology and structural features of the NDC particles can be varied by changing the concentration of oxygen in the gaseous mixtures. The particles of NDC can serve as reinforcements in metal matrix composites and additives imparting electrical conductivity to polymer matrix composites. Before NDC can be considered for industrial applications, it is necessary to address the related biological safety concerns. The present work was aimed at determining the cytotoxicity of NDC. The NDC powders with two morphologies (obtained using different acetylene/oxygen ratios) were tested on HEK293A human cells. The NDC powder was added to the culture medium in concentrations ranging from 10 ng/mL to 400 μg/mL. The cell viability was determined by a colorimetric EZ4U test and a real-time cell analyzer xCELLigence. None of the NDC samples showed a cytotoxic effect. The results of this study allow us to recommend NDC as a safe and useful product for the development of advanced carbon-based and composite materials.

ZrC+TiC synergically reinforced metal matrix composites with micro/nanoscale reinforcements prepared by laser powder bed fusion

The addition of hybrid ceramic reinforcing phases provides the possibility of regulating the in-situ reaction and effective strengthening in laser additive manufactured aluminum matrix composites (AMCs). In this work, AMCs reinforced with (ZrC + TiC) solid solution ceramics with micro/nanoscale microstructural features are fabricated by laser powder bed fusion (LPBF). The influence of laser power on the manufacturing quality, the microhardness and the wear properties of the LPBF-fabricated (ZrC + TiC)/Al composites is investigated. Moreover, the reaction mechanism between the ZrC and TiC ceramics in the LPBF process is revealed. The tensile properties of the (ZrC + TiC)/Al composites with different (ZrC + TiC) contents prepared at optimal process parameters are compared. During the LPBF process, the ZrC and TiC ceramics are incompletely melted. On the ceramic particles, a thin (Ti,Zr)C layer formed and large amounts of (Ti,Zr)C nanoparticles precipitated via a dissolution-precipitation mechanism. When the laser power increases from 375 to 425 W, the manufacturing quality, microhardness, tensile and wear properties of the (ZrC + TiC)/Al composites increase. The tensile strength of 10 wt.% (ZrC + TiC)/Al composites prepared at optimal processing parameters reaches a high strength value of ∼227 MPa with a uniform elongation of ∼6.7%, which is three times higher than that of the unreinforced Al-matrix. This is ascribed to the combined effects of Orowan strengthening, coefficient of thermal expansion (CTE) mismatch strengthening, load-bearing strengthening and grain refinement strengthening.

Mechanical behavior and interfacial micro-zones of SiCp(CNT) hybrid reinforced aluminum matrix composites

Micro-sized silicon carbide particles (SiCp) reinforced aluminum (Al) matrix composites have been widely used in the aerospace, electronics and transportation applications. However, due to the easily formed stress concentration in the SiCp/Al interfacial micro-zones, the large-sized SiCp may cause serious plastic loss of SiCp/Al composites that have limited their applications. In this study, the 14.5 μm SiCp was selected to prepare the SiCp(CNT) hybrid reinforcement, and then the 15 wt. % SiCp/Al and SiCp(CNT)/Al composites were fabricated by the vacuum hot-pressing sintering, respectively. Compared to the SiCp/Al composite, the SiCp(CNT)/Al composites own the larger mechanical properties such as the Young's modulus, the yield strength and the tensile strength. Among these composites, the SiCp(0.5CNT)/Al composite presents the best matching of strength and plasticity as a result of the existence of CNTs in the SiCp/Al interfacial micro-zones. Strengthening and toughening effects of CNTs in the SiCp/Al interfacial micro-zones can contribute to: 1) increasing the punched zone size around the SiCp; 2) increasing the dislocation density in the SiCp/Al interfacial micro-zones; 3) changing the dislocation distributions in the SiCp/Al interfacial micro-zones; 4) pinning the dislocation movements by CNTs in the SiCp/Al interfacial micro-zones. From the analysis above, the strengthening and toughening mechanism of the CNTs introduced in the SiCp/Al interfacial micro-zones of SiCp(CNT)/Al composites can be revealed, which can be further developed to guide and prepare the hybrid particles reinforced metal matrix composites. • The strength-plasticity matching relationship of SiCp/Al composites can be improved by the presence of CNTs at the interface micro-zones. • Compared with SiCp/Al composites, the introduction of CNTs can increase the dislocation density at the interface micro-zones and pin the dislocation movement. • The existence of CNTs can change the dislocation distribution of SiCp/Al interface micro-zones.

Synthesis and Characterization of Novel Nickel Coated Carbon Fibre Rod Reinforced Aluminium Metal Matrix Composite Material for using in Automobile Application

A carbon fibre (CF) in the form of a rod (continuous fibre) was used as reinforcement due to its superior strength and modulus properties. Carbon fibre rod reinforced aluminium 6061 alloy metal matrix composite material was synthesized using the stir casting liquid metallurgy route. Aluminium based metal matrix composite materials are light in weight. Very few researchers were worked on carbon fibre rod reinforced metal matrix composites (MMC). Electroless nickel deposition on carbon fibre rods (2mm and 3mm diameter) were carried out for improvement in wettability. On carbon fibre rods, the effectiveness of electroless nickel coating was validated using SEM (scanning electron microscopy) and EDAX (Energy Dispersive X-Ray Spectroscopy) analysis. A further coating thickness of nickel was improved using nickel electroplating. In a cast iron mould, nickel-coated carbon fibre rods were arranged in a circular pattern. Completely degassed molten aluminium 6061 alloy was poured in cast iron mould at 600-700 °C. The enhancement in Tribological and mechanical properties is always a prerequisite for technological advancement in automobile sector. From synthesized composites (11.11% Vol. CF and 25% Vol. CF reinforcement) specimen were prepared for density tests, bulk and microhardness tests, friction and wear tests. Synthesized composite has low density, increased bulk and microhardness, low coefficient of friction and reduced wear rate in comparison with aluminium 6061 alloy. Keywords: Carbon Fibre (CF) rod, MMC, Nickel coating, Casting, Mechanical, Tribological

Design of zero thermal expansion and high thermal conductivity in machinable xLFCS/Cu metal matrix composites

Materials having good comprehensive performances, such as zero thermal expansion (ZTE), high thermal conductivity, and machinability are in great demand for electronics, precision instruments, and aerospace applications. However, the challenge is that very few materials meet such requirements. In this study, a multicomponent reinforcement with negative thermal expansion (NTE) is designed for metal matrix composites (MMCs) to achieve wide-temperature-range ZTE, high thermal conductivity, and certain machinability. Taking advantage of the giant NTE in La(Fe,Co,Si)13 system, its originally narrow NTE temperature range can be broadened in the multicomponent material (xLFCS). When xLFCS is used as a reinforcement in MMCs and combined with copper, the thermal expansion coefficient of the xLFCS/39.7 vol%Cu composite can be adjusted to nearly zero (−0.2 × 10−6 K−1) over a wide temperature range of 200–320 K. The thermal conductivity of this composite is 44.1 W m−1 K−1, which is about seven times that of LFCS itself. In addition, compared with other ZTE metal-based materials, the present composite has good machinability. This work reports a metal matrix composite with high thermophysical properties and proposes an easy-to-operate method for broadening the temperature range of NTE or ZTE.

Influence of Supersaturation on Growth Behavior and Mechanical Properties of Polycrystalline 3C-SiC on W Wire Substrate

As an important reinforcement for metal matrix composites, the microstructure and mechanical properties of W-core SiC filament have drawn increasing attentions among researchers. In this work, the growth behavior of polycrystalline 3C-SiC on W-wire substrate in the chemical vapor deposition (CVD) process and the evolution of mechanical properties in preparation of W-core SiC filament, were investigated as a function of gas-phase supersaturation. Kinetic studies revealed that the growth of 3C-SiC grains was limited by surface reactions at both 850 °C and 1050 °C, and the deposit experienced similar morphological changes from a porous structure to large clusters, with the increase in supersaturation. Structural analyses and mechanical tests show that the production of pores and the amorphous phase with a low supersaturation, of 9.6 × 107 at 850 °C, resulted in a reduction in the modulus and hardness of the polycrystalline deposits, to 270.3 GPa and 33.9 GPa, while the reduced structural defects (e.g., stacking faults and twins) in highly (111) orientated 3C-SiC grains, as well as the improved surface quality obtained with the medium supersaturation of 1.6 × 107 at 1050 °C, enhanced the tensile strength and the Weibull modulus of W-core SiC filament to 2.88 GPa and 11.2, respectively. During the growth of 3C-SiC grains, the variation in structural defects density is controlled by the critical nucleation energy of the two-dimensional (2D) nucleus.

Manufacturing of Ceramic Reinforced Metal Matrix Composites (Al/Sicp) And Their Characterization Through Powder Metallurgy Methods

Metal Matrix Composites is two or more combination material with aluminum metal as matrix and devolved to fix metal act, strength, high temperature stability and hardness. Metal matrix composites have been developed so many because it has low density, corrosion proof, cheap and easy fabrication. Powder metallurgy technique is one of metal matrix composites fabrication process in solid state that is still developed because more economic, doesn't need difficult equipment. Aluminum that use in this research is Al alloy type 2124. Metal matrix composites fabrication process with powder metallurgy method using wet mixing with pure ethanol, cold compaction 300 MPa and inert gas atmospheric using Nitrogen gas (N2) at sintering process. Variation of sinter temperature that used is 450, 500, 550, and 600 oC with highly temperature average 5 oC/min and holding time for 1 hour and with speed flow Nitrogen gas (N2) 5 lt/min with pressure 1000 kgf/cm2. From research result can be concluded the mechanical properties and physical properties from metal matrix composites reinforced ceramics Al/SiCp increase with sinter temperature highly and with reinforcement particle addition SiC can increase mechanical properties and physical properties such as: hardness, wear resistance, coefficient of thermal expansion and corrosion resistance. From microstructure analysis, particle Sic distributed homogeneously at test specimen based on SEM analysis, and structure crystal analysis test result XRD show that dominant phase appear is Al, and Sic.

Investigation of surface integrity transition of SiCp/Al composites based on specific cutting energy during ultrasonic elliptical vibration assisted cutting

Different from brittle materials or homogeneous metal materials, there is no obvious characteristic of brittle removal or plastic removal in machining of particle reinforced metal matrix composites (MMCs). In the present work, we investigate the surface integrity transition of SiCp/Al composites during ultrasonic elliptical vibration-assisted cutting (UEVC). The machined surface is divided into two parts: plastic deformation of metal matrix and defects caused by particle deformation. A specific-cutting-energy-based criterion based on the relationship between plastic deformation and defects formation, is established to characterize the surface integrity transition of SiCp/Al composites quantitatively. The effectiveness of the critical cutting parameter is verified by systematic experiments. Experimental results show that the surface integrity transition of SiCp/Al composites is mainly affected by processing method and cutting speed. When the scratching speed increases from 100 mm/min to 200 mm/min, the main part of machined surface changes from defects to plastic deformation accordingly in UEVC. The ductile surface of SiCp/Al composites can be obtained when the cutting speed, cutting depth and feed rate are 100 mm/min, 0.01 mm and 0.02 mm/rev, respectively. According to the experimental results, particle partial fracture, debonding and micro-deflection dominate particle removal process in UEVC, which is also the main reason why UEVC can improve the machinability of SiCp/Al composites.

Micro/nano-reinforcements in bimodal-grained matrix: A heterostructure strategy for toughening particulate reinforced metal matrix composites

To overcome strength-ductility trade-off in particulate metal matrix composites (PRMMCs), we developed a novel and controllable strategy, for the first time, via a combination of micro/nano-reinforcements and ultrafine/coarse-grained (UFG/CG) matrices. A powder assembly was developed to fabricate micro B4Cp/6061Al composites, which features UFG/CG matrices containing ex/in-situ nano dispersoids and exhibits superior combination of strength and ductility. It was found that such a novel architecture possesses both intrinsic and extrinsic toughening. As the intrinsic toughening mechanisms, enhanced dislocation storage capability of UFG regions, twinning, and hetero-deformation induced toughening were detected. Moreover, crack-deflection induced by nano dispersoids as well as crack-blunting at UFG/CG regions were considered as the main extrinsic toughening mechanisms. The proposed strategy can be applied to design the architecture of other PRMMCs with both high strength and high ductility. Aluminum alloys; Powder processing; Heterostructures; Particulate reinforced composites; Microstructural toughening

Fabrication of Titanium and Copper-Coated Diamond/Copper Composites via Selective Laser Melting.

The poor wettability and weak interfacial bonding of diamond/copper composites are due to the incompatibility between diamond and copper which are inorganic nonmetallic and metallic material, respectively, which limit their further application in next-generation heat management materials. Coating copper and titanium on the diamond particle surface could effectively modify and improve the wettability of the diamond/copper interface via electroless plating and evaporation methods, respectively. Here, these dense and complex composites were successfully three-dimensionally printed via selective laser melting. A high thermal conductivity (TC, 336 W/mK) was produced by 3D printing 1 vol.% copper-coated diamond/copper mixed powders at an energy density of 300 J/mm3 (laser power = 180 W and scanning rate = 200 mm/s). 1 and 3 vol.% copper-coated diamond/copper composites had lower coefficients of thermal expansions and higher TCs. They also had stronger bending strengths than the corresponding titanium-coated diamond/copper composites. The interface between copper matrix and diamond reinforcement was well bonded, and there was no cracking in the 1 vol.% copper-coated diamond/copper composite sample. The optimization of the printing parameters and strategy herein is beneficial to develop new approaches for the further construction of a wider range of micro-sized diamond particles reinforced metal matrix composites.

Effect mechanism of mono-particles or hybrid-particles on the thermophysical characteristics and mechanical properties of Cu matrix composites

The nature of ceramic particles plays a decisive role in the performance of the ceramic/metal composites. This work is designed to deeply analyze the effect of mono-particles and hybrid-particles on the thermal and mechanical characteristics of the composites by means of experiment and finite element analysis. The in-situ TiB2/Cu and (TiC + TiB2)/Cu composites were fabricated by reactive hot pressing in Cu–Ti–B and Cu–Ti–B4C reaction systems. The two kinds of composites have similar coefficient of thermal expansion, while the (TiC + TiB2)/Cu composite demonstrates higher thermal conductivity and better compression properties than the TiB2/Cu composite. Simulations suggest that the spherical TiC particles in the (TiC + TiB2)/Cu composite optimize the heat transfer path and improve the stress distribution and plastic deformation, which are the main reasons for the difference in composite properties. Besides, the TiB2/Cu composite demonstrates excellent wear resistance due to the pinning effect of the hexagonal columnar particles. This would help deepen the understanding of the strengthening mechanism of mono-particles or hybrid-particles ceramic reinforced metal matrix composites and have a significant guiding role in the microstructure design and synergy optimization of composite.

Influence of the residual oxygen amount in reduced graphene nanoplatelets on microstructure and mechanical properties of ZK60 matrix composites

Graphene nanoplatelets (GNPs) are commonly regarded as an ideal reinforcement for metal matrix composites because of their excellent mechanical properties. However, these excellent properties cannot be fully exploited due to GNPs aggregation and poor bonding interface. In the present investigation, GNPs with different residual oxygen amount were prepared by adjusting the amount of KMnO4 oxidant using the modified Hummers method as well as thermal reduction. The GNPs-reinforced ZK60 matrix composites (GNPs/ZK60) were prepared through stir casting. Structure characterization indicates there are C–O, C–O–C and C–CO oxygen-containing functional groups on the synthesized GNPs, among which all C–CO and parts of C–O groups are broken and react with Mg to form MgO particles. The formed interfaces in terms of MgO in the GNPs/ZK60 composites are MgO/Mg, having a semi-coherent interface structure, and MgO/GNPs, having an incoherent interface structure. The sandwich interface structure of Mg/MgO/GNPs improves the interface bonding, in which the ultimate tensile strength and elongation of the 0.05 wt.%GNPs-4/ZK60 composite reached 261 MPa and 12.1%, increasing 37.4% and 128.3%, respectively, compared with those of the monolithic matrix. It is suggested the present work might offer a design guideline for graphene reinforced metal matrix composites.

Numerical study on the warm compaction and solid-state sintering of TiC/316L composite powders from particulate scale

Powder compaction and sintering are critical stages of powder metallurgy in manufacturing high performance particle reinforced metal matrix composites. In this paper, particulate scale numerical investigations on the warm compaction and solid-state sintering of TiC/316L composite powders with different particle size ratios (PSRs, R316L/RTiC) and TiC contents were performed using multi-particle finite element method (MPFEM) in two dimensions. The effects of PSR and TiC content, compaction pressure and temperature, and sintering temperature on the compaction and sintering processes were comprehensively analyzed. On this basis, a variety of macro- and microscopic analyses were conducted to further identify the densification dynamics and mechanisms. The results indicate that green compacts with higher relative density and more uniform stress distribution can be readily achieved by warm compaction. The large-scale plastic deformation of 316L particles caused by the cooperative actions of temperature and pressure is the main densification mechanism in warm compaction. During solid-state sintering, the improvement of relative density is mainly achieved by the vanishing or shrinkage of residual pores along with the growth of sintering necks, accompanied by the deformation of 316L particles. Large displacements of particles mainly occur in contacting areas of adjacent particles. Moreover, the equivalent stress in 316L particles is smaller than that in TiC particles. With the increase of PSR and TiC content, lower relative density of green compacts and sintered parts were obtained and more irregular morphologies of 316L particles can be observed.

A novel method for generation of particle packing model used in numerical simulation for the mechanical behavior of multi-component material

This study presents a novel algorithm to establish a numerical model for the study of mechanical behavior of multi-component material such as particle reinforced metal matrix composites, concrete, particle filled polymers, etc. The algorithm consists of two steps, one is to divide the given region into sub-regions of a specified size distribution, and the other is to fill each sub-region with particles of specified shapes. During the filling process, the contact states between particles can be controlled by the number and positions of reference points. Taking the quasi-static uniaxial tensile simulation of concrete as a verification example, two concrete models with the same particle size distribution but different shapes have been established. Through the comparison of elastoplastic responses of different aggregate shape models in different tensile directions, it is concluded that the models meet the requirements of macroscopic uniformity, meso-scale randomness and statistical rationality. This verifies the feasibility of modeling method and its advantages in precise control of particle shape, distribution and other parameters.

Wire–powder–arc additive manufacturing: A viable strategy to fabricate carbide ceramic/aluminum alloy multi-material structures

Ceramic/metal composites have been widely studied and applied because of their many advantageous properties. However, limited work on the additive manufacturing (AM) of ceramic controllably reinforced metal matrix composites (MMCs) has been conducted. To customize the compositions and properties at user-defined positions within a single MMC component, we developed a low-cost method, wire–powder–arc additive manufacturing (WPA-AM), for the rapid fabrication of ceramic particles to selectively reinforce aluminum matrix composite (AMC) structures. Multi-material AMC components with the controllable addition of various carbide ceramic particles (B 4 C, SiC, TiC, and WC/W 2 C) have been successfully fabricated via the WPA-AM system. We investigated the effects of the four kinds of ceramic particles on the arc behaviors, the droplet transfer modes in the WPA-AM process, and the forming qualities of the deposited AMC layers. The particle distribution, microstructures, and interfacial characteristics of the AMC structures have been studied. Furthermore, the mechanical properties of the single-AMC and the cyclic laminated multi-AMC structures were comparatively analyzed. This work verified the feasibility of manufacturing ceramic/metal multi-material structures by the WPA-AM process, which will promote the development and application of AM technology.

An overview of the effect of stirrer design on the mechanical properties of Aluminium Alloy Matrix Composites fabricated by stir casting

An overview of the effect of stirrer design on the mechanical properties of Aluminium Alloy Matrix Composites fabricated by stir casting