Special Issue Paper : High Temperature Thermo-mechanical Properties of HfC Reinforced Tungsten Matrix Composites

( Malik Adeel Umer ),( Dong Ju Lee ),( Ho Jin Ryu ),( Soon Hyung Hong ) 한국복합재료학회 2015 Composites research Vol.28 No.6

In order to improve the mechanical properties of tungsten at room and elevated temperature, hafnium carbide (HfC) reinforced tungsten matrix composites were prepared using the spark plasma sintering technique. The effect of HfC content on the compressive strength and flexural strength of the tungsten composites was investigated. Mechanical properties of the composites were also measured at elevated temperatures and their trends, with varying reinforcement volume fraction, were studied. The effect of reinforcement fraction on the thermal properties of the composites was investigated. The thermal conductivity and diffusivity of the composites decreased with increasing temperature and reinforcement volume fraction. An inherently low thermal conductivity of the reinforcement as well as interfacial losses was responsible for lower values of thermal conductivity of the composites. Values of coefficient of thermal expansion of the composites were observed to increase with HfC volume fraction.

Study of mechanical behavior of BNNT-reinforced aluminum composites using molecular dynamics simulations

Cong, Ziyu,Lee, Seungjun Elsevier 2018 COMPOSITE STRUCTURES -BARKING THEN OXFORD- Vol.194 No.-

<P><B>Abstract</B></P> <P>Fabrication of metallic matrix boron nitride nanotubes (BNNT) composites have remained challenging due to their high reactivity of metals at elevated processing temperatures. Recently, however, the successful fabrication of BNNT-metal composites has been reported using a plasma technique. Since carbon nanotubes (CNT), which are a structural analogy of BNNTs, easily react with aluminum to form aluminum carbides at the interface, serving as mechanically weak points, BNNTs can be a good alternative for the reinforcing component of metal-matrix composites (MMC). In this study, we conducted several molecular dynamics (MD) simulations to investigate the mechanical behaviors of BNNT-Al composites under tensile loading. The simulations provided quantitative information on the mechanical properties of the BNNT composite, revealing the effect of various BNNT diameters and volume fractions. The contributions of the BNNT and Al component to the total improvement of mechanical properties were quantified through a component analysis. The analysis revealed that the effect of the volume fraction of BNNTs is more significant than that of the size. In addition, the quantified relation between the volume fraction of BNNTs and the enhancement in elasticity can be effectively used for the engineering design of BNNT-Al MMCs.</P>

Synthetization and investigation on mechanical characteristics of aluminium alloy 7075 with TiB2 composite

M. Manoj,G.R. Jinu,T. Muthuramalingam,R. Leo Bright Singh 한양대학교 세라믹연구소 2021 Journal of Ceramic Processing Research Vol.22 No.4

The ceramic particles reinforced with aluminium metal matrix composites(AMMCs) has found its usage in variousapplications due to its distinct performance parameters. In the present study, an effort was made to synthesize and analysethe mechanical characteristics of TiB2 reinforced Al7075 metal matrix composites (MMCs) using stir casting technique byvarying the weight percentage of TiB2. The micro Vickers hardness, tensile strength, flexural properties are considered as theperformance measures in the present investigation. It was found that the addition of TiB2 could enhance the mechanicalcharacteristics of the MMCs significantly. The enhancement in hardness of the MMCs is due to the amalgamation of rigorousreinforcement in the matrix. The TiB2 reinforcement in the matrix alloy was found to increase the tensile and flexural strengthof AMMCs considerably. The TiB2 particles are consistently disseminated in aluminium matrix alloy with considerablebonding strength.

Fabrication and mechanical properties of metal matrix composite with homogeneously dispersed ceramic particles

Kim, Eun-Hee,Cho, Geun-Ho,Lee, Je-Hyun,Jung, Yeon-Gil,Yoo, YoungSoo,Seo, SeongMoon Elsevier 2013 Ceramics international Vol.39 No.6

<P><B>Abstract</B></P> <P>Titanium carbide (TiC) particles were coated with nickel (Ni) to increase their compatibility with a metal matrix, leading to an improvement in the dispersibility of TiC particles in the molten matrix. TiC particles were dispersed into a basic aqueous solution of pH 12, and then nickel nitrate (Ni(NO<SUB>3</SUB>)<SUB>2</SUB>), as a Ni precursor, was added to the TiC suspension. The interaction between the TiC particles and the Ni precursor is driven by the attractive force between the Ni cations and the TiC particles with negative charge. An inoculant (ferrosilicon), which has been used in the foundry industry to improve crystal growth of graphite, was used as a core particle. The Ni-treated TiC particles were coated onto the surface of the inoculant using an inorganic binder converted into its glass phase by sol–gel reactions. The reinforcement particles prepared through the dual-coating process were then injected into the molten matrix based on iron at 1500°C. The crystal phase of the graphite is more finely and shortly grown in the reinforced metal matrix than in that without the reinforcement particles. This means that the reinforcement particles are homogeneously and uniformly dispersed into the matrix without any aggregation of particles, implying that the mechanical properties of the reinforced matrix would be greater than those of a non-reinforced matrix. Consequently, metal matrix composites with reasonable properties can be fabricated successfully using the reinforcement particles prepared by the dual-coating process.</P>

High temperature ablation resistance of ZrN_p reinforced W matrix composites

Umer, M.A.,Lee, D.,Ryu, H.J.,Hong, S.H. MPR Pub. Services 2014 INTERNATIONAL JOURNAL OF REFRACTORY METALS AND HAR Vol.42 No.-

For the purpose of improving the high temperature ablation resistance of tungsten-based materials, a new class of composites was fabricated using particulate ZrN as reinforcement. The high temperature ablation behavior of the composites was investigated using oxyacetylene torch. Three different volume contents (up to 30vol.%) of ZrN were added to tungsten. It was observed that the addition of ZrN particles significantly enhanced the ablation resistance of the tungsten composites. Higher volume fraction of ZrN particles resulted in lower ablation rates. It was observed that ZrN particles, when exposed to the flame, formed a stable oxidation layer of ZrO<SUB>2</SUB> on the surface of the sample. This layer prevents further damage to the tungsten matrix, thus resulting in lower ablation rates. The effect of ZrN reinforcement content on the thermal behavior of the tungsten-based composites was also investigated. Thermal conductivity of the composites was seen to decrease as a function of temperature and reinforcement content. Lower values of thermal conductivity are helpful in enhancing the elevated temperature performance of the composites.

Synergetic Effect of Discontinuous Carbon Fibers and Graphite Flakes on Thermo-Mechanical Properties of Aluminum Matrix Composites Fabricated by Solid–Liquid Phase Sintering

Nabil Chamroune,Florence Delange,Nathalie Caillault,Fabrice Morvan,Yongfeng Lu,Akira Kawasaki,Jean‑François Silvain 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.2

Aluminum (Al) matrix composite materials reinforced with graphite fakes (GF) and pitch-based carbon fbers (CF) werefabricated by solid–liquid phase sintering with a small amount of Aluminum–Silicon eutectic alloy (Al-12 wt%Si). Theamount of Al–Si is optimized for a carbon content of 50 vol% in order to achieve, in the plane of GF reinforcement, a higherthermal conductivity (TC) and a lower coefcient of thermal expansion (CTE) compared to identical composite material fabricated by conventional powder metallurgy route. Al/(GF+CF) composite materials were characterized by scanning electronmicroscopy (SEM), energy-dispersive X-ray microscopy and X-ray tomography in order to highlight the distribution of theAl–Si liquid phase and the formation of a carbon network in the aluminum matrix. A small amount of CF allows to controlthe through-plane CTE without afecting signifcantly the in-plane TC of the Al-C composites. The (GF+CF) mixture andthe solid–liquid phase sintering allow to achieve a TC of 410 W/m K (in-plane direction) and a CTE of 2.4×10−6/K (troughplane direction), which is, for example, applicable for lightweight heat sink material.

Experimental Assessment for Aluminum-Based Metal Matrix Composites Reinforced with SiC Particles in Surface Grinding

Jae-Seob Kwak 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.6

This study aimed to evaluate grinding performance of aluminum-based MMCs reinforced with SiC particles. The grinding performance that a lot of process parameters deeply interacted was examined by design of experiments. From analyzing the effect of process parameters on the surface roughness and the grinding force, the optimal sets at process parameters were determined to improve the grinding performance for the aluminum-based MMCs. Second-order statistical models for predicting the surface roughness and the grinding force were also developed by means of the response surface method. Contour plots from the developed response surface models were useful for selecting one of the complicated grinding conditions.

Review on the Influence of Different Reinforcements on the Microstructure and Wear Behavior of Functionally Graded Aluminum Matrix Composites by Centrifugal Casting

Bassiouny Saleh,Jinghua Jiang,Aibin Ma,Dan Song,Donghui Yang,Qiong Xu 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.7

The main objective of the present paper is to draw the attention of researchers towards the wear analysis of functionallygraded aluminum matrix composites (FGAMCs) reinforced with different types of particles. The quality of the productsand characteristics achieved by the functionally graded materials (FGMs) has been given increasing attention during recentdecades. FGMs provide a way to obtain gradients between two phases with variations of properties. The centrifuge castingprocess was used to produce continuous variation of graded materials. These continuous graded materials offer high strengthand enhanced wear resistances compared with traditional composite materials. This paper summarizes the effect of the variousreinforcement materials and wear test parameters on microstructure as well as wear properties in the FGAMCs obtainedthrough the centrifugal casting technique. The results found in the reviewed literature are classified according to types ofreinforcement particles (such as silicon carbide, alumina and boron carbide) and the influence of wear test parameters (suchas applied load, sliding distance, duration and sliding speed) on FGM composites. The main conclusions in this paper arederived from previous studies on experimental investigations on the wear characteristics of FGAMCs. The research gapsand future directions have been discussed which will be prolific to the researchers in the design and manufacture of FGMsproduction by centrifugal casting.

Investigation on the Effect of Stirring Process Parameters on the Dispersion of SiC Particles Inside Melting Crucible

Vishal R. Mehta,Mayur P. Sutaria 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.8

Stirring based liquid metal processing is the widely explored process by researchers for the production of metal matrixcomposites (MMCs). The dispersion of reinforcement particles is the major challenge in the process. The stirring processparameters govern the dispersion of reinforcement particles in MMCs. The important stirring process parameters are stirringspeed, stirrer geometry, stirrer position, and stirring time. In the literature, research works are reported, where the effect ofsuch parameters on the dispersion of particles was investigated either by analyzing flow field using computational methods(assuming constant fluid properties) or by sectioning the casted samples. In cast condition, the dispersion of particles is alsoinfluenced by the solidification phenomena. The aim of the present work is to investigate the significance and the effect ofstirrer geometry, stirrer position and stirring speed on the dispersion of reinforcement particles inside melting crucible, duringthe stirring. Aluminium alloy LM25 was used as the matrix material and silicon carbide (SiC) particles having mean size37.58 microns (d50 value) were used as the reinforcement phases. Samples of the composite slurry during the stirring processwere dragged using a quartz tube at three levels inside crucible and microstructure analysis was carried out. Number density(ND) and inter particle distance were evaluated for parameter combinations. The uniform dispersion of SiC particles wasobserved at 45° stirrer blade angle, 400 rpm stirring speed and 40 mm stirrer position. And, significance order of individualparameter was observed as stirring speed < stirrer position < stirrer blade angle.

Elastoplastic modeling of circular fiber-reinforced ductile matrix composites considering a finite RVE

Kim, B.R.,Lee, H.K. Elsevier 2010 International journal of solids and structures Vol.47 No.6

<P><B>Abstract</B></P><P>A micromechanical elastoplastic damage model considering a finite RVE is proposed to predict the overall elastoplastic damage behavior of circular fiber-reinforced ductile (matrix) composites. The constitutive damage model proposed in our preceding work (<ce:cross-ref refid='bib19'>Kim and Lee, 2009</ce:cross-ref>) considering a finite Eshelby’s tensor (<ce:cross-refs refid='bib23 bib35'>Li et al., 2005; Wang et al., 2005</ce:cross-refs>) is extended to accommodate the elastoplastic behavior of the composites. On the basis of the exterior-point Eshelby’s tensor for circular inclusions and the ensemble-averaged effective yield criterion, a micromechanical framework for predicting the effective elastoplastic damage behavior of ductile composites is derived. A series of numerical simulations are carried out to illustrate stress–strain response of the proposed micromechanical framework and to examine the influence of a Weibull parameter on the elastoplastic behavior of the composites. Furthermore, comparisons between the present predictions and experimental data available in the literature are made to further assess the predictive capability of the proposed model.</P>