Wear Resistance Of Hybrid Composites Research Articles

Enhanced hardness and wear resistance of Al-based hybrid MMCs by using of composite metal boride reinforcement particles

Composite metal boride particles were synthesized and then used as the reinforcement material for fabricating Al-based hybrid metal matrix composites (MMCs). Mechanical alloying and pressureless sintering methods were used to produce the Al - 2 wt % Co–Ni–B/Co–Ti–B hybrid composites. Mechanically alloyed powders and sintered composites were characterized in terms of physical, microstructural and mechanical properties. The low crystallite size of Al particles and high density of the composites provided improved microstructures without needle-shaped secondary phases, and increased nanohardness values of Al matrix, and hence resulted in enhanced mechanical properties. The lowest indentation depths (both for matrix and reinforcement phases), the highest hardness (∼2 GPa) and the lowest wear volume loss (∼0.13 mm3) were obtained from the Al-based MMCs reinforced with Co–Ni–B particles containing CoB and Ni2Co0.67B0.33 phases. Studies revealed that the synergetic effect of the binary and ternary boride phases in the composite reinforcements had a positive role on the hardness and wear resistance of hybrid composites.

Influence of glass/carbon fiber stacking sequence on mechanical and three-body abrasive wear resistance of hybrid composites

Glass and carbon fiber reinforced polymer hybrid composites are the need of the hour to overcome the weakness of individual fibers. The mechanical and abrasive wear property of the hybrid composites needs to be evaluated to ascertain the feasibility in structural and tribological applications. In this article, hybrid composites of different stacking sequence such as [G3C2]S, [GCG2C]S and[G2C2G]S has been designed. The flexural strength and three body abrasive wear resistance of the hybrid composites were evaluated and compared among themselves. It is observed that the flexural strength and modulus of [GCG2C]S type hybrid composite was improved by 46.1% and 49.5% respectively as compared to plain glass fiber reinforced polymer composites. The specific wear rate was evaluated by three-body abrasive wear at different operating parameters and optimized the same through response surface methodology. Box–Behnken design of the experiment was adopted to design the experiments. The model has predicted the minimum specific wear rate for [GCG2C]S hybrid composite is18.8476 × 10–3 mm3 Nm−1 at applied load of 33.15 N and sliding distance of 1100 m. The model predicted results were compared with experimental one and found a good agreement between them. The worn surface of the composites was analyzed by scanning electron microscope to understand the wear mechanism.

Mechanical and dry sliding wear behaviour of B4C and rice husk ash reinfroced Al 7075 alloy hybrid composite for armors application by using taguchi techniques

These research works investigate, the mechanical and dry sliding behaviour of AA7075-B4C-rice husk ash (RHA) hybrid alloy composite. The specimens of AA7075 with 0, 2, 4, 6, 8 wt% of B4C mixed with 0, 2, 4, 6 and 8 wt% rice husk ash (RHA) are prepared using high vacuum casting machining to study the dry sliding wear behaviour at room temperature. The surface study is used to characterize the fabricated hybrid AA7075 composites. The mechanical behaviour, hardness, flexural tests are conducted using respective ASTM standards. The maximum hardness of 128 HV is obtained for AA7075-8 wt% B4C – 8 wt% rice husk ash (RHA) hybrid composite. The maximum tensile, compressive and flexural strength obtained to be 270 MPa, 570 MPa and 480 MPa respectively, at 8 wt% B4C – 8 wt% of RHA. RHA and B4C particles improved the wear resistance of hybrid composites and decreased the damage on the worn surface. The obtained results are also optimized and observed that addition of 8 wt% B4C – 8 wt% of RHA have reduced wear rate of composite greatly even with increasing sliding velocity and the applied load. Thus, the wear resistance of composite improves at 8 wt% B4C – 8 wt% of RHA.

Investigation on mechanical properties and dry sliding wear characterization of stir cast LM13 aluminium alloy-ZrB2-TiC particulate hybrid composites

In this study, the ceramic particles of titanium carbide (TiC) and zirconium diboride (ZrB2) were used as reinforcements in LM13 alloy matrix to fabricate hybrid composites. The composites along with unreinforced aluminium alloy were produced by varying the weight percentage (wt%) of ZrB2 (0, 2.5, 5 and 10) with a constant 5 wt% TiC through liquid metallurgy stir casting technique. Microstructural analysis of cast samples was made using optical microscope. Various mechanical characteristics such as hardness, tensile strength and ductility were evaluated for the composites and unreinforced aluminium alloy to investigate the effect of different wt% of reinforcements in LM13 alloy matrix. Dry sliding wear performance of the pin samples of LM13 alloy and composites was examined using a pin-on-disk tribometer to study the influence of sliding distance and wt% of reinforcements on the responses like weight loss, wear rate and friction coefficient. Fractured surface of tensile test samples and dry sliding worn surface of pin samples were analyzed through field emission scanning electron microscope. From the experimental study, it is observed that the trend of hardness, tensile strength and wear resistance of hybrid composites increases proportionately with increasing ZrB2 wt% in LM13 matrix. The degree of wear in pin samples exhibited an inverse relationship with the sliding distance after a run of 500 m. Cumulative weight loss of the composites depicted an increasing trend with the applied load during wear test. As compared to unreinforced LM13 aluminium alloy, the hardness, ultimate tensile strength and wear resistance of LM13-10ZrB2-5TiC hybrid composite increased up to 63%, 49% and 69% respectively. FESEM worn surface analysis results indicated the transition of wear mechanism from mild abrasive wear to severe delamination with increasing load. ZrB2 and TiC particle reinforced hybrid composites offered better mechanical and tribological properties than TiC reinforced composite and LM13 alloy.

Formation of lubricated tribo layer, grain boundary precipitates, and white spots on titanium-coated graphite–reinforced hybrid composites

In this present investigation, AA7050 hybrid composite reinforced with boron carbide (B4Cp) and graphite (Gr) was fabricated through stir casting. The AA7050/B4Cp/Gr hybrid composites were prepared with 7.5 wt.% boron carbide particles added with 2.5, 5, 7.5 and 10 wt.% of graphite. Addition of potassium titanium fluoride (K2TiF6) flux improved the bonding of matrix and reinforcement due to the titanium interface. The influence of graphite particles on mechanical, wear, sulphide stress corrosion cracking and electric discharge machining was analysed. A new wear equation for graphite-reinforced composites based on transient wear equation and Archard’s equation was derived. The hardness, tensile strength and wear resistance of hybrid composites reduce with increase in graphite weight percentage. The graphite-reinforced hybrid composites showed improvement in sulphide stress corrosion cracking due to grain boundary precipitates. The material removal rate of hybrid composites increases with increase in graphite weight percentage, and it exhibits poor surface finish due to poor heat dissipation.

Dry sliding Wear Behavior of Hybrid aluminum Metal Matrix composite reinforced with Boron carbide and graphite particles

Aluminum (Al-2219) is reinforced with 8% Boron carbide and 3% Graphite particles. Aluminum alloy hybrid metal matrix composites (HMMCs) are prepared by stir casting Technique. Dry sliding wear test is conducted by pin on disc apparatus at room temperature on pure base alloy Al-2219, mono and hybrid composite. The wear behavior of composites was studied by various parameters such as applied load; sliding speed and sliding distance were taken for this study. The result shows that wear rate increase with increase in load and sliding distance. Wear resistance of hybrid composite is higher than mono composite material. The worn out surface was analyzed by SEM.

Dry sliding wear of heat treated hybrid metal matrix composites

In recent years, there has been an ever-increasing demand for enhancing mechanical properties of Aluminum Matrix Composites (AMCs), which are finding wide applications in the field of aerospace, automobile, defence etc,. Among all available aluminium alloys, Al6061 is extensively used owing to its excellent wear resistance and ease of processing. Newer techniques of improving the hardness and wear resistance of Al6061 by dispersing an appropriate mixture of hard ceramic powder and whiskers in the aluminium alloy are gaining popularity. The conventional aluminium based composites possess only one type of reinforcements. Addition of hard reinforcements such as silicon carbide, alumina, titanium carbide, improves hardness, strength and wear resistance of the composites. However, these composites possessing hard reinforcement do posses several problems during their machining operation. AMCs reinforced with particles of Gr have been reported to be possessing better wear characteristics owing to the reduced wear because of formation of a thin layer of Gr particles, which prevents metal to metal contact of the sliding surfaces. Further, heat treatment has a profound influence on mechanical properties of heat treatable aluminium alloys and its composites. For a solutionising temperature of 5500C, solutionising duration of 1hr, ageing temperature of 1750C, quenching media and ageing duration significantly alters mechanical properties of both aluminium alloy and its composites. In the light of the above, the present paper aims at developing aluminium based hybrid metal matrix composites containing both silicon carbide and graphite and characterize their mechanical properties by subjecting it to heat treatment. Results indicate that increase of graphite content increases wear resistance of hybrid composites reinforced with constant SiC reinforcement. Further heat treatment has a profound influence on the wear resistance of the matrix alloy as well as its hybrid composites. For all the heat treatment processes studied ice quenching with ageing duration of 6hrs resulted in improved wear resistance of both the unreinforced matrix alloy and its hybrid composites.

STUDY OF WEAR BEHAVIOUR OF Al/ (Al2O3P and SiCP) HYBRID METAL MATRIX COMPOSITES

In this study, dry sliding wear behaviour of Aluminium Hybrid Metal Matrix Composite was investigated and a prediction model was developed using Taguchi’s method. Aluminium A356alloy reinforced with equal weight percentage of alumina and silicon carbide particles (10wt%, 20wt% and 30wt %) was produced using liquid metallurgy method. Experiments were conducted using Pin-on-disc tester. The sliding distance was kept constant and the effect of load, sliding velocity and weight percentage of reinforcement on the wear properties was evaluated. It was found that as load increases, wear rate also increases and it decreases as sliding velocity increases. By increasing weight percentage of reinforcements, the wear resistance increases and was found that 30% reinforced composite had less wear rate. The prediction model showed that the major parameter that influences the wear rate was load followed by weight percentage of reinforcement and sliding velocity. By confirmation test, the predicted wear rates were found to be close to the experimental values. Based on this approach, it was found that the improvement in the wear resistance of hybrid composites became more significant at high sliding velocity, low load and with high weight percentage of reinforcements. Keywords: Dry sliding wear, Metal Matrix Composite, Alumina, Silicon carbide, Prediction model, Taguchi’s method

Influences of counterface materials and reinforcements on the sliding wear of copper matrix composites

Abstract The influences of counterface materials and reinforcements on the sliding wear behavior of copper matrix composites have been investigated. Experiments were performed using a block-on-ring type wear machine on which SiC/Cu and (SiC+Gr)/Cu hybrid composites were slid against various counterfaces, i. e. GCr15 bearing steel, 45 medium carbide steel and AlSi alloy. Experimental results show that increasing counterface hardness is in favor of the establishment of a wear resistant mechanically mixed layer (MML) on SiC/Cu composite, while massive materials transfer and seizure take place when tested against soft counterface. The wear resistance of hybrid composite is improved by forming a graphite-rich MML, and the hardness of steel counterfaces does not influence the wear behavior obviously. The graphite film formed on the two sliding surfaces alleviates materials transfer and avoids the occurrence of seizure with soft counterface.