Nano-sized Al2O3 Particles Research Articles

Effect of reinforcement particle size on the corrosion and mechanical properties of spark plasma sintered aluminium matrix composites.

In this study, the effects of different sizes of reinforcing particles on the corrosion behaviour and mechanical properties of aluminium (Al)-based composites produced by spark plasma sintering (SPS) are analysed. In the study, the effects of SPS parameters, including electrical power, applied pressure and sintering temperature, on the consolidation process and microstructure evolution of the composite are closely investigated. The results reveal a nuanced relationship between the sintering conditions and the properties of the particles, which in turn determine the sintering dynamics and the formation of the microstructural features. The evaluation of mechanical properties indicates a remarkable influence of particle size distribution on the hardness of the composites, showing an initial improvement with the introduction of nanoparticles, followed by a slight decrease as the balance between nano- and micron-sized Al2O3 particles shifts. A scanning electron microscopy (SEM) study demonstrates the influence of particle dimensions on the change of grain boundaries and the spatial arrangement of the composite matrix. Electrochemical experiments in a 0.1M NaCl solution show a consistent corrosion potential (Ecorr) across all samples, while the current densities associated with corrosion (icorr) show considerable variation. The presence of nano-sized Al2O3 particles was found to increase corrosion resistance, in contrast to the detrimental effects observed with larger microparticles. In particular, composites with a bimodal distribution of particle sizes showed a 3.5-fold increase in corrosion resistance compared to pure Al. The specific Al-2n8mAl2O3 composite that exhibited active electrochemical properties at elevated potentials without a defined passivation range emphasises the significant role of particle size. This study draws attention to bimodal microstructures as a promising route to achieving uniformity and improved corrosion resistance in Al matrix composites, while pointing to the need for further research to fully elucidate the operative mechanisms.

Friction stir welding of constrained groove pressed Al1050 using Al2O3 nanoparticles

In this investigation, two passes Constrained Groove Pressed (CGPed) Al1050 sheets went through Friction Stir Welding (FSW) by adding nano-sized Al2O3 particles. Then, the microstructure and mechanical properties of the welded joints, undergone various pass numbers and rotational to traverse speed (ω/ν) ratios, were presented. Findings showed all joints were fractured from the SZ, although HAZ softening happened due to grain growth in this region. The presence of the Al2O3 particles in the stir zone led to a fine and equiaxed grain structure, resulting from continuous dynamic recrystallization (CDRX) during the high-temperature welding process. This grain refinement contributed to an improvement in the mechanical properties of the joints, such as strength and microhardness. Employing two different ω/ν ratios resulted in a variety of thermal cycles during the welding procedure such that the peak temperature in the ω/ν of 70 and 25 r/mm reached ∼423 °C and ∼285 °C, respectively. Microstructure studies via optical observation and EBSD analysis illustrated that employing a higher ω/ν ratio and weld pass number resulted in more uniform particle distribution in the stir zone thanks to facilitating materials flow and incorporation during FSW. As a result, the three passes FSWed sample at the higher ω/ν ratio of 70 r/mm showed the most homogeneous particle distribution and finest grain structure in the SZ. This microstructure evolution was in reliable agreement with the mechanical performance of the joints. The three passes FSWed sample at the higher ω/ν ratio of 70 r/mm demonstrated the highest weld strength, microhardness, and %elongation compared to other FSWed joints. This sample showed an ultimate tensile strength (UTS) of ∼97 MPa and a %elongation of ∼16%, and its mean microhardness value had a ∼3.5% increase compared to the CGPed base metal. Conversely, the one pass FSWed sample at the lower ω/ν ratio of 25 r/mm represented the weakest mechanical properties due to cavities, defects, and agglomerated Al2O3 nanoparticles. The presence of nanoparticles was a decisive factor in microstructural evolution during the welding, thereby increasing the mechanical quality of the joints dependent upon their uniform dispersion, obtained by increasing the pass number and ω/ν ratio.

Effect of Porosity on the Thermo-Mechanical Behavior of Friction-Stir-Welded Spark-Plasma-Sintered Aluminum Matrix Composites with Bimodal Micro- and Nano-Sized Reinforcing Al2O3 Particles

The thermo-mechanical behavior of nanosized Al2O3 particles reinforcing aluminum was analyzed in the present paper. The material was prepared by spark plasma sintering and friction stir welding. The thermal stresses affecting the composite behavior during welding were modeled through COMSOL MultiPhysics, and the results were validated by the analyses of the composites’ mechanical properties. The spark-plasma-sintered materials presented limited porosity, which was taken into account during the modeling phase. Both model and experiments revealed that higher heat input is related to better material mixing during welding and sound mechanical properties. Thermal stresses lead to residual stresses close to 300 MPa in the thermo-mechanically affected zone for processing conditions of 1900 RPM and 37 mm/min. This leads to an increase in hardness up to 72 HV.

Influence of quasi-crystal particles and processing condition on microstructure and tensile properties of a selective laser melted high entropy alloy

Quasi-crystal (QC) Al65Cu20Fe10Cr5 powder particles were added into CoCrFeMnNi high entropy alloy (HEA) and processed by selective laser melting (SLM) under different conditions with the aim of enhancing their strengths. It is shown that increased energy density leads to increased grain size and texture in the SLMed HEA but does not cause significant influence on tensile properties. With the addition of QC particles, the microstructure and tensile properties highly depend on input energy density. Thus, HEA-10 wt% QC samples made between 55.6 J/mm3 and 92.6 J/mm3 are dominated by dispersive columnar γ grains and arc-shaped B2 phase and nano-sized Al2O3 particles while those made with high energy densities such as 133.3 J/mm3 contain mixed large vertical and horizontal columnar γ grains but no B2 phase. The B2-containing HEA-10 wt% QC samples show remarkably enhanced yield strength and ultimate tensile strength, thanks to B2 and nano-sized Al2O3 particles acting as effective dislocation motion barriers. The B2-free HEA-10 wt% QC samples show reduced strengths which is attributed to their large and complex grain structure and dendritic structure.

A Novel Treatment: Effects of Nano-Sized and Micro-Sized Al2O3 on Steel Surface for the Shear Strength of Epoxy-Steel Single-Lap Joints.

Traditional steel surface treatment (e.g., sand blasting, or silane treatment) was regarded as an effective method to improve the bonding strength of steel–epoxy single-lap joints. In the present study, a new steel surface treatment method was developed. With this method, the steel surfaces were treated with suspensions of nano-sized and micro-sized Al2O3 particles in ethanol/water mixture using the dip-coating method. Both Al2O3 particle sizes were previously treated or not treated with silane. Single-lap shear tests of the steel–epoxy bonds were conducted to compare the effects of the treating methods. According to the testing results, the highest increase in the bonding strength (by 51.8%) was found for the steel coated with the suspension of silane treated nano-Al2O3 particles. Scanning electron microscopy (SEM) analysis and energy dispersive spectrometer (EDS) analysis indicates that the nano-Al2O3 particles were clearly attached to the treated steel surfaces. Moreover, the steel surface with the silane-treated nano-Al2O3 particles was found to clearly enhance the contact angle between the steel and epoxy resin. The fracture morphology analysis of the single-lap shear testing specimen shows that the bonding between the steel and adhesive changed from steel–epoxy interfacial failure to cohesive failure when the steel surfaces were treated with the nano-Al2O3 particles suspension. The developed steel surface treatment method with the suspension of nano-particles proves to be effective and reliable in enhancing the bonding strength of the steel-to-epoxy adhesives.

Influence of Nano-sized Al2O3 Reinforcements on the Mechanical Behavior of the Al7075 Composites

Aims: Al7075 is a well-defined alloy for its excellent physical and mechanical behavior, such as high strength, toughness, and low density. To reach the expectations of the automobile and aerospace applications, the properties of Al7075 alloy have to be improved by reinforcing nano-sized Al2O3 particles. Objectives: Synthesis and characterization of the Al7075 alloy reinforced with Al2O3 nano particles for different structural engineering applications. Methods: In this present work, nano-sized Al2O3 particles were added and dispersed homogeneously using a stir casting technique. AA7076/Al2O3 composites were prepared by varying wt.% percent of Al2O3 reinforcement particles (0.75, 1, 1.25, 1.5. 1.75 and 2 wt.% (weight-percentage)). Results: The SEM micrographs reveal the homogeneous distribution of Al2O3 reinforcements along the grain boundaries of the Al7075 matrix material. The experimental test results showed that the addition of Al2O3 reinforcements and the mechanical properties of the Al7075/Al2O3 composite improved as compared to the Al7075 matrix material. Conclusion: The composite with 1.5 wt.% Al2O3 showed higher strength and hardness as compared to other reinforcements.

Microstructure and mechanical characterization of Cu–Ni/Al2O3 nanocomposites fabricated using a novel in situ reactive synthesis

Chemical-based synthesis of co-formed oxide (CuO–NiO–Al2O3) nanoparticles, followed by selective hydrogen reduction of the Cu and Ni oxides and ultimately consolidation into pellets, produced various compositions of Cu–Ni/Al2O3 nanocomposites. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy analyses were used to characterize the powders. The generated powders ranged in size from 20 to 70 nm, with a considerable presence of agglomerates. According to SEM examination, the powders were homogeneous in shape and particle size. Cold pressed nanocomposite powders were sintered for 2 h at 950 °C. SEM with energy dispersive spectroscopy (EDS) was also used to study the microstructure of the sintered specimens. In addition, the physical and mechanical properties of sintered specimens were studied. When the Al2O3 content increased, a more uniform distribution of nanosized Al2O3 particles in the Cu–Ni matrix was attained, resulting in a reduction in particle size. The results also demonstrated that as the Al2O3 concentration was raised, the microhardness and compressive strength of the nanocomposites rose by 74% and 67% compared to pure alloy, with the exception of fracture strain, which decreased dramatically.

Mechanical and tribological properties of nano-sized Al2O3 particles on ADC12 alloy composites with Strontium modifier produced by stir casting method

Nano-Al2O3 particles were incorporated into ADC12 alloy with the addition of Al-5Ti-B, Al-Sr, and Mg to achieve high performance in mechanical and tribological properties. In this study, varied nano-Al2O3 was used from 0.25 vf-% to 0.5 vf-% through stir casting methods to discover the optimum amount to obtain high performance. Besides, the inclusion of grain refiner Al-5Ti-B and microstructure modifier Al-Sr is expected to improve performance to the next level. However, porosity and agglomeration still be a concern in Aluminum alloy matrix composite fabrication. The presence of spinel phase MgAl2O4 in the interface area between nano-Al2O3 particles and ADC12 alloy is relied upon to minimize this porosity and agglomeration issue. The optimum of tensile strength and hardness was found at 0.35 vf-% Al2O3 and wear rate at 0.4 vf%. Although, the optimum point of wear found at 0.4 vf%, porosity began to increase at 0.4 vf% as well. As a result, 0.35 vf% addition of the nano-Al2O3 gives the best performance for the composite.

A facile route to prepare ODS WC[sbnd]Co cemented carbides

Oxide dispersion strengthened (ODS) WCCo cemented carbides with excellent mechanical properties were prepared by a facile three-step method. First, the mixture of ammonium paratungstate, cobalt oxalate and aluminum nitrate nonahydrate were roasted to generate precursor powder. Then, the precursor powder was reacted with insufficient carbon black to remove oxygen to aid precise carbon addition in the next step. Finally, depending on the carbon content difference between carbothermic reduction products and target product, the sample was mixed with the required carbon black to prepare WCCoAl2O3 cemented carbides directly by the method of powder sintering. Experiments showed that after the addition of uniformly distributed nano-sized Al2O3 particles, the mechanical properties included hardness and toughness of ODS cemented carbides improved. When the content of Al2O3 was 0.5%, the densification of finally prepared WC-5.5wt%Co-0.5wt%Al2O3 alloy could reach to 99.08%, and the values of fracture toughness and Vickers hardness were 11.35 ± 0.60 MPa·m1/2 and 1756 ± 20.92 HV, respectively, thus giving excellent results.

Low cycle fatigue behavior of magnesium matrix nanocomposite at ambient and elevated temperatures

AZ31B alloy reinforced by 1.5 vol.% nano-sized Al2O3 particles has been subjected to fully-reversed strain-controlled uniaxial tension-compression cyclic loading at room temperature, 100 °C, and 200 °C. A combination of mechanical and magnetic stir casting methods followed by a hot-extrusion process was used to fabricate the composite material. Cyclic and fatigue behaviors of the composite were studied at the strain ranges of 0.8%–2.5%. The experimental results of the fatigue lives were used to assess and compare the life prediction capabilities of different existing strain-based and energy-based fatigue models. The results exhibited that the presence of the nano-sized reinforcing particles leads to a homogenously fine microstructure and slightly changes the texture of the composite extrusion, compared to the typical microstructure and texture of monolithic AZ31B extrusion. The cyclic behavior of the composite is altered from an asymmetric shape at room temperature to a symmetric one at 200 °C, resulting in reduction of mean stress. Unlike the room-temperature behavior, twinning and detwinning are not governing plastic deformation mechanisms at the elevated temperatures, especially at 200 °C. Cyclic softening occurs by increasing the temperature, in a manner similar to the monotonic tensile tests. Due to the strain-controlled loading and increasing the composite ductility at the elevated temperatures, the fatigue lives are comparable at the different temperatures. Finally, considering the results at all the temperatures, Jahed-Varvani (JV) as an energy-based model shows a more promising life prediction.

Direct recovery of LiCoO2 from the recycled lithium-ion batteries via structure restoration

The efficient reutilization of electrode materials in waste lithium-ion batteries (LIBs) is an urgent and tough problem that grows along with the rapid increase in the use of LIBs in various areas, including portable electronic products, electric vehicles and backup power supplies. Herein, we propose a promising way to recover the LiCoO2 positive electrode material from the recycled LIBs via structure restoration. The collected spent LiCoO2 powder is mixed with lithium salts and sintered to form a sophisticated layered structure. When Li2CO3 is added as the lithium source and the mole ratio of lithium to cobalt is controlled at 1.00 in the mixture, a layered structure of regenerated LiCoO2 could be preferably obtained at a calcination temperature of 800 °C. To improve the electrochemical performance of the regenerated LiCoO2, nanosized Al2O3 particles are coated on the surface of the regenerated LiCoO2. The Al2O3-coated and regenerated LiCoO2 demonstrates comparable properties to those of commercial LiCoO2 materials. The regeneration of spent LiCoO2 via structure restoration, which is demonstrated in the present study, provides an effective way to reuse cobalt metal directly without traditional leaching and re-synthesis procedures, which reduces energy consumption and contributes to the environmental protection.

Micro-Alloying and Surface Texturing of Ti-6Al-4V Alloy by Embedding Nanoparticles Using Gas Tungsten Arc Welding

Titanium alloy Ti-6Al-4V is known for both its excellent mechanical properties and its low surface hardness. This study explores a two-step process for depositing a hard nanocrystalline coating onto the surface of the Ti-alloy, followed by surface melting, which embeds hard nanoparticles into a thin surface layer of the alloy. The treated surface layer was studied using X-ray diffraction, scanning electron microscopy, and Vicker’s micro-hardness testing. The results of the study show that the surface of the Ti-6Al-4V alloy can be successfully hardened by embedding nanosized Al2O3 particles into the surface using gas tungsten arc welding to melt the surface of the material. Surface melting the Ti-6Al-4V alloy with a 50A welding current produced the maximum microhardness of 701 HV0.2kg. The micro-hardness of the treated surface layer decreased with the increasing size of the nanoparticles, while the roughness of the surface increased with the increasing welding current. The heat input into the surface during the surface melting process resulted in the formation of various intermetallic compounds capable of further increasing the hardness of the Ti-6Al-4V surface.

Effects of relative humidity, particle hygroscopicity, and filter hydrophilicity on filtration performance of hollow fiber air filters

The aims of this study are to fabricate hollow fiber air filters with different hydrophilicity and investigate their filtration performance against different particles under different relative humidity. In this study, three types of hollow fibers were prepared: a hydrophilic PAN hollow fiber, a hydrophobic PVDF hollow fiber, and a dual layer PAN/PVDF hollow fiber. The three hollow fibers were used to filtrate nano-sized NaCl (hygroscopic) and Al2O3 (non-hygroscopic) particles at RH 80% and 40%. The results showed that the filtration efficiency was not affected by RH, particle hygroscopicity and filter hydrophilicity whereas the pressure drop across membranes was influenced significantly. When filtrating NaCl particles at RH80%, a RH higher than deliquescent point of NaCl, the PAN hollow fiber had a quick pressure drop increase initially whereas the pressure drop of the PVDF hollow fiber only increased dramatically at a later stage. In contrast, the PAN/PVDF hollow fiber always displayed the lowest pressure drop increment. When filtrating Al2O3 particles at RH 80%, the PAN hollow fiber showed a higher pressure drop increment than PAN/PVDF and PVDF hollow fibers. For the filtration at RH 40%, the pressure drops of all hollow fibers were independent of particle hygroscopicity and filter hydrophilicity. Overall, the PAN/PVDF dual layer hollow fiber had the best filtration performance at all experimental conditions. The mechanisms of particle deposition at different filtration conditions have been elucidated. These findings may provide useful insights to design next-generation air filters suitable for filtrating various aerosol particles in a wide range of RH.

Combination of Mechanical and Electromagnetic Stirring to Distribute Nano-Sized Al2O3 Particles in Magnesium Matrix Composite

In this article, a novel stirring method has been developed for producing metal matrix nanocomposites, in which two different stirring methods, i.e. mechanical and electromagnetic stirrings, have been used simultaneously. Mechanical stirring might not be sufficient enough to break nano-agglomerations properly. Moreover, this method makes some unwanted porosities and gas entrapments in the composites. On the other hand, the electromagnetic stirring as a sort of body force (with no considerable shear stresses) could be used up to solidification decreasing the dendritic microstructures, gas entrapments, and undesirable agglomerations and impurities. Applying these both stirring methods simultaneously as an electromagnetic-mechanical stirring method, the distribution of reinforcing nanoparticles throughout the matrix phase would be more desirable due to better stirring conditions. In addition, since it is a simple and applicable approach, it can be used for mass production. Magnesium/Al2O3 nanocomposite with volume fractions of 0.5, 1.0, and 1.5% have been fabricated accordingly and then hot-extruded at 350°C using 20 : 1 extrusion ratio. According to the scanning electron microscopy (SEM) results, the nanoparticles have an appropriate distribution in the matrix. Also, comparing the results of microstructural evaluation and Vickers microhardness, tension and compression tests, it was observed that the grain size was decreased and the hardness and yield stress (in both tension and compression tests) were improved by adding more nanoparticles to magnesium matrix.

Friction-stir welding of AA6061-T6: The effects of Al2O3 nano-particles addition

In the present work, attempts were made to fabricate Al-based nanocomposites by Friction Stir Welding (FSW) process. Al2O3 nanoparticles were added into the aluminum matrix for refining the microstructure of the nugget zone (NZ) and to restrict the growth of granularly in the heat-affected zone (HAZ). The effects of Al2O3 nanoparticles addition on the grains structure evolution and various mechanical behavior of friction stir welded aluminum matrix was studied and elaborated in detail. The findings revealed that the addition of Al2O3 nanoparticles resulted in remarkable refining of grains in the nugget zone due to pinning effect produced by nano-sized Al2O3 particles which prevent the grain growth followed by recrystallization during FSW, leading to a remarkable reduction in grain size. A significant increment in tensile strength, micro-hardness and wear properties compared to sample without nanoparticles under the same operating conditions is attributed to nano-sized Al2O3 particles addition in the nugget zone. Also, the samples joined with rotating and transverse velocities of 2000 rpm and 70/80 mm/min showed higher tensile properties. However, the employment of single FSW pass resulted in an unusual Al2O3 nanoparticles distribution and void initiation at the interface between Al-matrix and Al2O3 nanoparticles in the heat-affected zone resulted in the sudden premature fracture of the specimen during tensile loading.

Influence of aging & varying weight fraction of Al2O3 particles on the mechanical behaviour & volumetric wear rate of Al 7075 alloy composite produced by liquid metallurgy route

The effect of heat treatment, particle size, varying weight% (2, 4, 6 and 8%) of Al2O3 particles on the mechanical and wear behaviour of Al 7075 alloy composite is investigated. Two sets of Al 7075 alloy composite samples reinforced separately with as-received (45 μm) Al2O3 particles and nano-sized (40–50 nm) Al2O3 particles were produced by stir casting route. The stir cast samples were initially solutionized and then artificially aged at 120 °C for durations of 3, 12, 24, 48, 60, 72, 84 and 96 h. The hardness, tensile, compression and pin on disc wear tests were carried out on the aged and non-aged samples. The mechanical test results showed an enhancement of the composites’ mechanical properties due to the effect of artificial aging and as well as the addition of varying wt% of (coarse or nano-sized) Al2O3 reinforcement. The T6-aged Al 7075 alloy composite specimens reinforced with nano-Al2O3 particles exhibited enhanced hardness, tensile and compression strength compared to the T6 aged and non-aged samples reinforced with coarse alumina reinforcement. An increasing trend was observed due to the addition of upto 6 wt% of Al2O3 reinforcement, beyond which the samples exhibited a decline in its tensile and compression strength. The tensile fracture surface of the samples was characterized by FESEM to determine the deformation mechanism. Pin on disc wear tests under varying load conditions revealed that the T6-aged composite samples showed higher wear resistance than the unreinforced Al 7075 alloy. Nonetheless, the T6-aged nano-Al2O3 reinforced samples showed superior resistance to wear loss compared to its coarse Al2O3 reinforced counterpart. The worn surface of the samples was characterized by FESEM to examine the mechanism of wear. The test samples were also characterized using XRD and EDS analysis.

Synthesis and characterization of a spun membrane with modified Al2O3

In this work, composite nanofiber membranes were prepared by adding modified nano-sized Al2O3-particles to a polyvinylidene fluoride (PVDF) solution (17 wt %) through an electrospinning process. Th...

Nanoindentation behavior of nanostructured bulk (Fe,Cr)Al and (Fe,Cr)Al-Al2O3 nanocomposites

The purpose of the present study was to design a new generation of FeAl-based intermetallic compounds with improved mechanical and oxidation properties. Synthesis of powders of FeAl, (Fe,Cr)Al and (Fe,Cr)Al in situ composites with 5 and 10% Al2O3 contents was reported elsewhere. In this paper the sintering behavior is reported. FeAl, (Fe,Cr)Al and (Fe,Cr)Al - Al2O3 powders were sintered by a hot-pressing method at 1600 °C and 5.5 GPa for 15 min to produce bulk specimens for mechanical and microstructural characterization. Microstructural characterization by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) of theses nanocomposites disclosed uniform distribution of Al2O3 nano-particles. XRD analysis indicated the presence of FeAl, (Fe,Cr)Al and Al2O3 phases. The presence of nano-sized Al2O3 particles effectively retarded grain growth by pinning the grain boundary during hot pressing. Nanoindentation tests indicated that with increasing content of Cr and Al2O3 reinforcement, the hardness and Young's modulus increased, and the fracture toughness reaches a high value of 19.6 ± 0.4 MPa m1/2 for the (Fe,Cr)Al-10%Al2O3 composition, with a hardness value of 21.7 ± 1.8 GPa. Nanoindentation creep tests at room temperature showed that composites with Al2O3 nanoparticles had higher creep rate than FeAl and (Fe,Cr)Al. It was found that improvements in the mechanical properties of FeAl intermetallic compound can be achieved by adding Cr and uniform distribution of Al2O3 nanoparticles.

Properties of AlSi9Cu3 metal matrix micro and nano composites produced via stir casting

Abstract The effects of micro and nano sized reinforcement particles on microstructure and mechanical properties of aluminium alloy-based metal matrix composites were investigated in this study. AlSi9Cu3 alloy was reinforced with micro and nano sized ceramic reinforcement particles at different weight fractions by using a stir casting method. The mechanical tests (hardness, three point bending) were performed to determine the mechanical properties of AlSi9Cu3 alloy-based microcomposites (AMMCs) and nanocomposites (AMMNCs). The experimental results have shown that the size and weight fraction of reinforcement particles have a strong influence on the microstructure and the mechanical properties of AlSi9Cu3 alloy-based microcomposites and nanocomposites. The relative densities of all AMMC and AMMNC samples are lower than unreinforced AlSi9Cu3 alloy due to porosity formation with the increase of weight fraction of reinforcement particles. As weight fraction increases, hardness values of AMMCs and AMMNCs increase. Maximum flexural strength can be obtained at 3.5wt.% for the AMMC sample with microsized Al2O3 particles and at 2wt.% for the AMMNC sample with nano-sized Al2O3 particles. After the weight fractions exceed these values, flexural strengths of both AMMCs and AMMNCs decrease due to clustering of Al2O3 particles.

Wear Behavior of Al-Based Nanocomposites Reinforced with Bimodal Micro- and Nano-Sized Al2O3 Particles Produced by Spark Plasma Sintering

Abstract Spark Plasma Sintering (SPS) has been recognized, in the recent past, as a very useful method to produce metal matrix composites with enhanced mechanical and wear properties. Obviously, the material’s final properties are strongly related to the reinforcement types and percentages and the particles’ distribution, as well as to the processing parameters employed during synthesis. The present article analyzes the effect of microscopic and nanometric alumina particles, blended to pure aluminum in different combinations, on the final properties of metal matrix composites produced via SPS. A strong variation in the microstructural behavior, mechanical, and wear properties has been observed by varying the nano- to micro-alumina particles’ percentage and the distribution of the ceramic particles blended with aluminum ones.