Effect of ZrB2 particles on the microstructure and mechanical properties of hybrid (ZrB2 + Al3Zr)/AA5052 insitu composites (original) (raw)
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Microstructure and Mechanical Behaviour of Al 6061-ZrB 2 In-situ Metal Matrix Composites
2016
Aluminium matrix composites processed through in-situ molten reaction has emerged as an alternative for eliminating defects existing in ex-situ reinforced metal matrix composites. Development of composites through in-situ method using inorganic salts via liquid metallurgy route is the most widely accepted technique. In the present work, Al6061-ZrB2 in-situ composites have been developed through in-situ reaction of Al-10%Zr and Al-3%B master alloys in Al6061 alloy. Study of microstructure and mechanical properties of in-situ reinforced ZrB2 in Al6061 alloy have been carried out. Composite exhibited grain refinement and improved the mechanical properties of Al6061 alloy. Ductility of composite is reduced with increase in content of ZrB2.
In the present work, ZrB 2 /Al alloy composites were processed through the salt-melt reaction technique. Aluminum alloy (LM4) was taken as a matrix material. The ZrB 2 reinforcement particles were formed in-situ by the reaction of precursor salts K 2 ZrF 6 and KBF 4 within the aluminum melt. Relative to the parent alloy, the hardness of the composites reinforced with 2.5, 5 and 7.5 wt.% ZrB 2 showed an increase of 8.24%, 17.64% and 33.77%, respectively. The tensile strength also improved initially but decreased when the amount of reinforcement exceeded 5-wt.%. The elongation varied in the same fashion as the tensile strength. The microstructure of the composites showed moderately uniform distribution of particles. However, agglomeration of reinforcement particles became a problem at the highest amount of reinforcement. Wear experiments to determine the influence of load, sliding velocity, sliding distance and the amount of reinforcement on the wear rate of composites were designed in accordance with the Taguchi model. The results revealed that both load and sliding velocity have the highest influence.
Some aspects of Cold Deformation studies of Al- ZrB 2 composites
— In the present study Al-ZrB2 composite were made by powder metallurgy route adding different amounts of synthesized ZrB2 powder (2, 4, 6, 8, 10 wt. %). The ZrB2 powder was synthesized by using self-propagating high temperature synthesis (SHS). The samples of different aspect ratios (0.35, 0.5 and 0.65) were made and then sintered at 550 o C under continuous argon gas atmosphere in a tubular furnace for 1 hour. The microstructure of the composites had shown that there is no chemical adhesion between Al matrix and ZrB2 reinforcement. Hardness of the composites increased with increase in the amount of ZrB2 reinforcement. The hardness of the composites increased with increase in amount of ZrB2 reinforcement. It was found that the formability stress index increased with the increase of preform fractional density and decreased with the aspect ratio. Relation between various stress ratios, axial strain and relative densities were analyzed. Statistical fitting methods are used on the curve drawn between the axial strain and the stress formability index. The compacts of lower aspect ratio and high initial preform density were found to have a very high fracture strain.
Materials Today: Proceedings, 2017
The present work focused on comparative study on the mechanical and thermal properties of Al alloy (A380)-5wt.%TiB 2 and Al alloy (A380)-5wt.%ZrB 2 particulate composites which were processed through in-situ reaction. The TiB 2 and ZrB 2 particle reinforced composites were produced through the salt-melt reaction of K 2 TiF 6 +KBF 4 and K 2 ZrF 6 +KBF 4, respectively, in the presence of aluminium melt. The formation of TiB 2 and ZrB 2 particles were confirmed by the XRD analysis. Between the two composites, the TiB 2 /A380 composite was found to have better tensile strength and hardness while the ZrB 2 /A380 composite displayed higher coefficient of thermal expansion (CTE). The properties were also compared with the parent aluminium and it is found that both composites have higher hardness but smaller tensile strength and CTE than the aluminium.
Vacuum, 2018
In the present study, the Al/Al alloy reinforced with ZrB 2 composite is produced by the combination of powder metallurgy (PM) and Vacuum arc melting (VAM) techniques. The composite powder is milled for homogenous composition and uniaxially cold compacted to form green compacts which are used as raw materials in VAM. The composites are remelted by tumbling the melts after completion of each melt to ensure homogenous composition. The composites are then ground to the core of the melt and metallographically mirror surface finished to examine the microstructure. Secondary phase CuAl 2 precipitates are formed due to the alloying effect between Cu and Al. The ZrB 2 reinforcement particles existed in groups along the grain boundaries and sparsely in the bulk of the composite. The hardness increased with the alloying effect and also with the addition of ZrB 2 reinforcement particles. The corrosion rate of the composite was evaluated by potentiodynamic polarization study. Corrosion rate increased with the presence of secondary phase particles.
Materials Today: Proceedings, 2023
This work explained about the hardness, density and tensile behavior of AMMCs and also recognizes the influence of Cr 3 C 2 into AA7075 under casting process on their mechanical properties. The composites are obtained through stir casting process with 2.5, 5 and 7.5 wt% of Cr 3 C 2. It is observed that the mechanical properties of the composites are increased with increasing weight percentage of reinforced material. The results are analyzed with optical micro structural images. The optimum hardness and tensile strength were observed at 5 wt% Cr 3 C 2 composite than other wt% of composites as well as monolithic base material.
International Journal of Engineering & Technology, 2019
Aluminium matrix composites by way of in-situ reaction has arisen as a preference conducive to knock out imperfections and defects exiting within ex situ MMC. In the present work, Al-Cu-ZrB2 have been develop through in situ reaction which boost mechanical properties over dispersion strengthening together with grain refinement obtained by the existence of each particulates inside the melt all along solidification. Al-Cu reinforced among different proportion of ZrB2 (0, 3 and 6 wt. %) synthesized using in situ fabrication at 800 °C of molten aluminum-copper alloys by inorganic salts K2ZrF6 together with KBF4. The amalgam were specified using XRD, FESEM together with mechanical test on appropriately sectioned and metallographically prepared surface to examine and inspect phase distribution, hardness together with tensile properties. From result acquired, raised ZrB2 amount will increase rate of tensile and hardness characteristics of Al-Cu alloy. XRD patterns exposed development of Zr...
IOP Conference Series: Materials Science and Engineering
Steel is used because of its high strength and toughness, but it has high density, therefore lighter material with comparable toughness is developed. One alternative is aluminum matrix composite with zirconia (ZrO 2) as the reinforcement with high fracture toughness. Al-9Zn-6Mg-3Si (wt. %) composites were developed with addition of 2.5, 5, and 7.5 vol. % ZrO 2 through squeeze casting. To improve toughness, the composite was solution treated at 450 o C for 1 h, then aged at 200 o C for 1 h. Materials characterization included Optical Emission Spectroscopy (OES), Rockwell B hardness testing, impact testing, fractography analysis, microstructure analysis using Optical microscope (OM) and Scanning Electron Microscope (SEM) / Energy Dispersive X-Ray Spectroscopy (EDS), as well as X-Ray Fluorescence (XRF). The results showed that the more ZrO 2 particles, the higher porosity and the lower the hardness and the impact values, both in as-cast condition and after ageing at 200 o C at 1 h.
Mechanical Characterization of Al 6061-Zircon Particulate Composites
Today composite materials gained popularity in their improved properties over the traditional materials, like low density, good thermal resistance , better corrosion resistance and surface finish. The Aluminium based metal matrix composites have the wide applications in Automotive and defence industries due to some good properties like strength to weight ratio, more wear resistance. In the present work Al6061 Alloy taken as the matrix alloy and zircon as the reinforcement , stir casting method was chosen to develop this composite. The melt composites in the graphite crucible were stirred by the mechanical stirrer and immediately it was poured to the cast iron moulds. Different samples of 0,3,6,9, and 12% of zircon were produced. Casted Samples were machined to ASTM standards. The Properties like tensile strength, impact strength ,Hardness and wear rate of the developed composites were investigated. For the 9% of reinforcement it has been observed a significant improvement in strength, hardness and reduction in the wear rate.
Journal of the Ceramic Society of Japan, 2019
ZrB 2 /ZrAlC composite ceramics were successfully synthesized from Zr, Al, graphite and ZrB 2 powders by using a spark plasma sintering method. The volume content of ZrAlC has a major impact on the fracture toughness. ZrAlC-rich (²70 vol.%) composite ceramics exhibit much higher fracture toughness than do ZrB 2-rich (²60 vol.%) composite ceramics. The evidently larger ZrAlC grains in the ZrAlC-rich composite ceramics lead to a longer crack propagation path for toughening. Both the Vickers hardness and Young's modulus of composite ceramics increase slightly with an increase in the ZrB 2 volume content. The evident oxidation of composite ceramics at 1000°C results in the formation of Al 18 B 4 O 33 and Al 4 B 2 O 9. At 1200°C, the composite ceramics exhibit a fluffy and porous top oxidized layer composed of whiskers of Al 18 B 4 O 33 and Al 4 B 2 O 9 grains, and the thickness of the oxidized layer and oxidation mass gain increase with an increase in the ZrAlC volume content. The ZrB 2-rich composite ceramics with less than 40 vol.% ZrAlC content do not exhibit apparently larger oxidation mass gain than does the pure ZrB 2 ceramic after oxidation at 1200°C and higher temperatures. The composition-dependent microstructure and properties provide a comprehensive insight for the development of high-temperature composite ceramics based on ZrAlC and ZrB 2 .