Reinforced Aluminum Matrix Composites Research Articles

Investigation of the Thermophysical Simulation and Material Removal Mechanism of the High-Volume-Fraction SiCp/Al Composite in Wire Electrical Discharge Machining.

SiC particle reinforced aluminum matrix composites (SiCp/Al) are widely used in aviation, weaponry, and automobiles because of their excellent service performance. Wire electrical discharge machining (WEDM) regardless of workpiece hardness has become an alternative method for processing SiCp/Al composites. In this paper, the temperature distribution and the discharge crater size of the SiCp/Al composite are simulated by a thermophysical model during a single-pulse discharge process (SPDP) based on the random distribution of SiC particles. The material removal mechanism of the SiCp/Al composite during the multi-pulse discharge process (MPDP) is revealed, and the surface roughness (Ra) of the SiCp/Al composite is predicted during the MPDP. The thermophysical model simulation results during the MPDP and experimental characterization data indicate that the removal mechanism of SiCp/Al composite material consists of the melting and vaporization of the aluminum matrix, as well as the heat decomposition and shedding of silicon carbide particles. Pulse-on time (Ton), pulse-off time (Toff), and servo voltage (SV) have a great influence on surface roughness. The Ra increases with an increase in Ton and SV, but decreases slightly with an increase in Toff. Moreover, compared with experimental data, the relative error of Ra calculated from the thermophysical model is 0.47-7.54%. This means that the developed thermophysical model has a good application and promotion value for the WEDM of metal matrix composite material.

Nanocrystalline NiTiB reinforced aluminum matrix composites: Synthesis, structural, mechanical and corrosion properties

In this study, aluminum composites were developed using a powder metallurgy route by incorporating varying amounts of nanocrystalline NiTiB into the Al2024 alloy. The effects of nanocrystalline NiTiB on the structural, morphological, corrosion, and mechanical properties of the aluminum composites were thoroughly investigated. The results showed that the base alloy and composites with 2% and 4% NiTiB exhibited the highest relative density. The composite with 4% NiTiB achieved the maximum hardness of 87.4 HV. Additionally, the inclusion of nanocrystalline NiTiB significantly improved the compressive strength, corrosion resistance, and wear resistance of the composites. Specifically, the compressive strength increased by approximately 2% with 2% NiTiB and by around 13% with 12% NiTiB. Corrosion resistance was highest in the composite with 4% NiTiB, as confirmed by electrochemical impedance spectroscopy. In the wear-loss study, the wear loss of the composites was found to be reduced by 244% and 457% for those reinforced with 2% and 12% NiTiB, respectively. These findings underscore the potential of nanocrystalline NiTiB to enhance the performance of Al2024 composites in applications demanding superior corrosion resistance, mechanical strength, and wear resistance.

Characterization of different size reinforcement effects on microstructural failure mechanism in carbon nanotube-reinforced aluminum composites

In this study, we investigated the effect of reinforcement sizes on the tensile strength and ductility of carbon nanotube (CNT)-reinforced aluminum matrix composites fabricated through ball milling, followed by hot extrusion of a powder encapsulated in an aluminum container. We analyzed the microstructural properties of the samples, including the aluminum grain size, its spatial variation with the alignment of CNT, and CNT length. Nanoindentation test results revealed the spatial variation of hardness and Young’s modulus of composites with small-diameter CNTs, indicating local Al4C3 formation and interlock structure resulting from dislocation accumulation during the fabrication process. This explains dimples of different sizes observed on the fracture surfaces of the samples and the occurrence of CNT pullout. Furthermore, we proposed the failure mechanism of the composites under tensile strain and calculated the failure strain using the Whitehouse–Clyne model. The calculated failure strain agrees well with the experimental values. The high ductility of the composites is attributed to the large grain fracture and rotation of neighboring grains due to the constraint imposed by CNTs.

Micro milling mechanism and tool wear of Unidirectional HfZrTiTaNbCu0.2 fiber reinforced aluminum matrix composites

This study delves into the micro milling and tool wear mechanisms of 2A97 aluminum matrix composites reinforced with HfZrTiTaNbCu0.2 fibers. Finite element analysis models the fibers as uniformly distributed cylindrical entities within the matrix, applying various material constitutive laws, failure, and evolution criteria to simulate milling at three specific angles (45°, 90°, 135°). The research examines the effects of milling parameters, fiber orientations, and tool coating thickness on cutting forces, temperatures, surface roughness, and tool wear. Key findings include: These forces escalate with both cutting speed and depth of cut. Notably, at a feed rate of 68 μm/z, the cutting force is 1.5 times higher compared to 58 μm/z.An increase in milling parameters leads to higher cutting temperatures. Differences of 12 °C and 10 °C were noted at varying depths of cut (10–25 μm) and cutting speeds (1000–1200 mm/s), respectively. As the fiber angle increases, cutting forces first decrease and then rise, with fibers oriented at 90° experiencing only 53 % of the force compared to those at 135°. Similarly, cutting temperatures follow this trend, with a 26 °C difference between 45° and 90° fibers. This factor is positively correlated with depth of cut and fiber angle. Surface roughness at a 55 μm depth is 4.3 times that at 10 μm, and 135° fibers show 2.7 times the roughness of 45° fibers. However, within feed rates of 48–58 μm/z and cutting speeds of 800–1200 mm/s, there is a notable decrease in surface roughness. Variations in cutting parameters, fiber orientations, and tool coating thickness significantly influence peak tool stress. Stress concentration at the central groove tends to reduce tool wear, whereas stress concentration at the peripheral edge or strain concentration at the bottom edge exacerbates it.

Microstructure evolution and mechanical properties of selective laser melting fabricated hybrid particle reinforced AlSi10Mg composites

(SiC+TiB2)/AlSi10Mg composite powders with 5 wt% micro-SiC particles and 1.5 wt% nano-TiB2 particles were prepared by high energy ball milling, and hybrid particle reinforced aluminum matrix composites (AMCs) were fabricated by SLM. This study systematically investigated the effects of SiC and TiB2 particles on the phase composition, microstructure evolution, grain crystallization, and mechanical properties. The machanisms of potential strengthening and fracture mechanisms were revealed. The tribological behaviors of the hybrid particle reinforced AlSi10Mg composites under different friction conditions were explored as well. The results show that the 1.5 wt% nano-TiB2 particles provided sufficient nucleation sites for grain growth, completely transforming from coarse columnar to fined equiaxed grains. The average grain size decreases from 7.98 μm to 3.34 μm, and the texture is significantly weakened, which is beneficial to the homogenization of the microstructure, thereby improving the mechanical properties of the SiC/AlSi10Mg composites. The (SiC+TiB2)/AlSi10Mg composites showed a high ultimate tensile strength (∼ 489.1 MP), hardness (172.2 HV) and elongation of 8.2 %. The enhancement of mechanical properties was attributed to Orowan strengthening, fine grain strengthening, and load-bearing strengthening. Due to the Si precipitates and fine microstructure, a low wear rate of 0.50 × 10−5 g/m was obtained, 10.7 % lower than that of SLM formed SiC/AlSi10Mg composites. The friction process is affected by abrasive wear, adhesive wear and delamination wear. It is aspired that the current approach can provide guidance for the design of new alloy systems with excellent performance.

Mechanical Effects of Carbon Nanotubes-Graphene Reinforced Aluminium Matrix Composites

In this paper, MWCNTs-GN hybrid reinforcement was prepared by wet ball milling process. The MWCNTs-GN/Al composites were prepared by high-energy ball milling and vacuum hot-pressure sintering. The MWCNTs-GN hybrid reinforcements and MWCNTs-GN/Al composites were characterised by SEM and TEM, and the synergistic effects of carbon nanotubes and graphene on the mechanical properties of the aluminium matrix composites were investigated by hardness and friction wear tests. The results show that the 0.5 wt.% MWCNTs-GN/Al composite has the best mechanical properties, with a hardness of 116.3 MPa which is 33.9% higher than that of pure aluminium, and the frictional properties of the MWCNTs-GN reinforced aluminium matrix composites have a lower coefficient of friction than that of pure aluminium. After the addition of more than 5 wt.% of the composite reinforcing phase, the wear rate increased slightly due to the reduced densities of the MWCNTs-GN/Al composites.

Tribological performance and mechanism of the titanium fiber-SiC whisker hybrid reinforced aluminum matrix composites prepared by pressure infiltration

In this contribution, a Ti-6Al-4V fiber (Tif) and SiCw (SiCw) hybrid reinforced 5056 Al composites (Tif + SiCw/5056 Al) were fabricated, and the effects of SiC whisker contents on the microstructure, mechanical properties, and wear resistance were investigated. The mechanical properties and the hardness of the composites increased first and then decreased with the increase of SiCw contents. The optimal ratio of SiCw to titanium fibers is 3 wt%. The flexural strength of the optimal composites reached 533 MPa, and the fracture toughness reached 29.1 MPa m1/2. Under a load of 40 N, compared with the Tif/5056 Al composites sample, the wear rate of the optimal composites sample decreased by 80.7 %. The uniformly dispersed SiC whiskers promote the formation of a mechanical mixing layer (MML) on the friction surface; the wear mechanism mainly involves abrasive wear and adhesive wear.

Study of bond strength and electronic properties at the 6H-SiC/Al interface: Based on first-principles calculations

As the medium between the reinforcement and the matrix, the interface plays a critical role in the mechanical properties of silicon carbide particle reinforced aluminum matrix composites. This study used first-principles calculation methods to systematically analyze 14 different 6H-SiC/Al low-index interfaces, including atomic configuration, interface bonding strength, and electronic structure and bonding principles between interfaces. The adhesion work calculations reveal that the C-top-SiC(0001)/Al (111) and SiC(0001)/Al (100) interfaces have larger adhesion work values, specifically 5.09 J/m2 and 5.021 J/m2, respectively. Additionally, the rigid tensile testing confirms that the tensile stress values at the interfaces of C-top-SiC(0001)/Al (111) and SiC(0001)/Al (100) are higher, measuring 36.4 GPa and 32.5 GPa, respectively. The above results show that the interface bonding strength of these two configurations is the highest, the most stable, and most likely to appear in the 6H-SiC/Al interface configuration. The results of the analysis on charge density difference and partial density of states indicate that the interfaces of C-top-SiC (0001)/Al (111) and SiC (0001)/Al (100) are primarily composed of strong ionic and covalent bonds.

Direct aging treatment of TiN modified Al–Mn–Sc alloy processed by laser powder bed fusion: On the microstructure evolution and mechanical property enhancement

In this study, the TiN nanoparticles modified Al–Mn-Sc composite and Al–Mn-Sc alloy have been fabricated by the laser powder bed fusion (LPBF). The microstructure, mechanical properties and strengthening mechanisms of these materials were discussed in details for both the as-built and artificial aged conditions. The results showed that the aged Al–Mn-Sc/TiN composite exhibits homogeneous nucleation with equiaxed grains ranging from 0.81 μm to 1.30 μm. After direct aging treatment of 300 °C, there are a volume fraction of secondary L12-Al3(Ti, Sc, Zr) nanoparticles precipitated in the composite sample, contributing to an ultra-high fracture strength of 701 ± 16 MPa. The increment in strength brought by TiN mainly comes from fine grains and high volume fraction of L12-Al3(Ti, Sc, Zr) nanoprecipitates. The fracture behaviors suggest that the uniform distribution of reinforced particles and less amount of micro pores can improve the strength and ductility of LPBF particle reinforced aluminum matrix composites.

Enhanced strength–ductility synergy of SiC particles reinforced aluminum matrix composite via dual configuration design of reinforcement and matrix

To overcome the strength-ductility conflict in particle reinforced aluminum matrix composites (PRAMCs), a novel dual configuration strategy of microstructure was proposed in this work. The dual configuration including both heterogeneous grain structure and hybrid reinforcements was obtained by powder metallurgy, which was designed as submicron-sized SiC particles (SiCsm)/Al and micron-sized SiC particles (SiCm)/2024Al components. Representative alternating coarse grain (CG) bands containing SiCm and ultra fine grain (UFG) bands with dispersed SiCsm were revealed in microstructural characterizations. Compared to corresponding homogeneous composites with the same fraction particles, the dual configuration composite achieved simultaneous enhancement in strength and ductility and remained a comparable Young’s modulus of 98GPa, which represented 442 MPa in yield strength, 590 MPa in ultimate strength and 8.7 % in fracture elongation. The extra strength provided by hetero-deformation induced (HDI) strengthening is a potential dominant strengthening mechanism. The intrinsic toughening mechanisms primarily contribute to HDI strain hardening and enhanced dislocation accumulation capacity, while the extrinsic toughening mechanisms presumably attribute to more uniform microcrack distribution and blunting effect of CG zones on cracks. Our work provides a feasible route including ball milling and powder assembly to preparate high-modulus aluminum matrix composites for strength-ductility balance design.

Abrasive wear behavior of functionally graded Al3Ti reinforced aluminum matrix composite

Abrasive wear behavior of functionally graded Al3Ti reinforced aluminum matrix composite

Microstructure and performance of carbon fiber reinforced aluminum matrix composites with molybdenum carbide coating on carbon fibers

In this work, a molybdenum carbide coating on the surface of short carbon fibers prepared using molten salt method was proposed to ameliorate the interfacial bonding and improve the performance of carbon fiber/Al composites. The carbon fiber/Al composites were produced using vacuum hot pressing. The characteristics of molybdenum carbide coating were analyzed. Besides, the microstructures, bending strength and thermal properties of the carbon fiber/Al composites were explored. Furthermore, the interfacial thermal resistance of the composites was investigated in relation to theoretical evaluations derived from the combined Maxwell-Garnett effective medium approach and acoustic mismatch model schemes. The results indicated that a homogeneous Mo2C coating with a thickness of 0.5 μm was obtained by proper molar ratio of carbon fibers, MoO3 and chloride salts mixture and heated at 1000 °C for 60 min. The Mo2C coating greatly enhanced the bond between the aluminum matrix and carbon fiber, leading to improvements in the densification behavior and bending strength of the coated composites. The enhanced thermal properties including improved thermal conductivity and reduced coefficient of thermal expansion (CTE) were also achieved by the Mo2C coating. The in-plane thermal conductivity of 60 vol.% Mo2C-coated carbon fiber/Al composite was 221 W·m−1·K−1 enhanced by 92% compared to that of uncoated composite and the CTE was 6.0 × 10–6 K−1 which was suitable for electronic packaging materials.

The fabrication of brass reinforced aluminum matrix composites by FSW

Brass sheet is added into the joining location in friction stir welding (FSW). Brass reinforced Al matrix composite is then formed in the FSW nugget zone with brass. A new microstructure based mechanical property model is proposed to predict both the microstructural evolutions and mechanical property changes in FSW with brass. The discrepancy between the numerical and experimental data is 0.77% for temperature, 2.2% for average grain size, and 6.4% for hardness. The change of temperature is very small in comparison of FSW and FSW with brass. However, compared to FSW, the hardness is obviously increased and the average grain size is decreased by 34.8% in FSW with brass in the nugget zone due to the pinning effect from the broken brass particles. The process parameters can be numerically tested to find the optimal design for experiment.

Enhanced interfacial bonding and mechanical properties of CeO2-coated graphene oxide reinforced 7075 composites

Severe interfacial reactions and interfacial bonding between graphene and Al matrix have been the main challenges to achieve high performance graphene reinforced aluminum matrix composites (AMCs). In this study, a new interfacial structure design was proposed to address the above challenges by coating CeO2 nanoparticles on the surface of graphene oxide (GO). Then, CeO2-coated GO reinforced 7075 (GO/7075) composites were successfully fabricated via ultrasonic assisted casting. It was found that the coated CeO2 on GO could react with Al matrix to form Al11Ce3 and suppress the formation of interfacial product Al4C3. Additionally, the as-formed Al11Ce3 at the interface served as a bridge to tightly bind the GO and Al, thus resulting in forming a strong interfacial bonding, which was favour to the load transfer. Moreover, when adding 1.5 wt% CeO2-coated GO, the average grain size of the composites reduced from 100.8 μm to 38.5 μm. As a result, the composite reinforced with 1.5 wt% CeO2-coated GO demonstrated enhanced mechanical properties with a yield strength of 263.4 MPa and an ultimate tensile strength of 342.8 MPa, 100.8% and 69.4% higher than those of unreinforced 7075 alloy, respectively. Furthermore, the strengthening mechanisms of CeO2-coated GO/7075 composites were discussed in detail.

Shear response and deformation mechanism of boron nitride nanosheets reinforced aluminum matrix composites

Atomistic simulations are performed to study the shear response and deformation mechanism of boron nitride nanosheet (BNNS) reinforced aluminum (Al) matrix composites. In this work, stacked BNNS/Al composites and dispersed BNNS/Al composites with various BNNS layers are constructed, respectively. Our computations show that the wrinkle deformation of BNNS under shear loading does not lead to the loss of load-bearing capacity. However, the yield of the Al matrix causes it to lose load-bearing capacity. The occurrence of wrinkles in BNNS aggravates the plastic failure of the Al matrix. High BNNS volume fraction increases the shear modulus and flow stress of stacked BNNS/Al composites but decreases the shear strength. Compared with stacked BNNS/Al composites, the mechanical properties of dispersed BNNS/Al composites are remarkably improved with the increase of BNNS interface in both elastic and plastic stages. In addition, the BNNS interface is able to obstruct the propagation of dislocations and stacking faults in the Al matrix. These findings may deepen our understanding of the mechanical properties and deformation mechanisms of BNNS/Al composites.

Electrochemical behavior and microstructural characterization of nano-SiC particles reinforced aluminum matrix composites prepared via friction stir processing

The present work aims to elucidate the mechanism of microstructural evolution in different regions of nano-SiC particles reinforced aluminum matrix composites prepared by friction stir processing (FSP) on its electrochemical behavior. Electron backscatter diffraction technique (EBSD) and transmission electron microscopy (TEM) were employed to characterize the microstructure evolution of stir zone (SZ), advancing side thermomechanically affected zone (AS-TMAZ), retreating side thermomechanically affected zone (RS-TMAZ) and base metal (BM). The electrochemical behaviors of the above zones were investigated using electrochemical tests. A homogeneous and fine microstructure is formed in SZ, not only the nano-SiC is homogeneously distributed within the grains with an average grain size of 3.5 μm, but also the recrystallized grains account for the highest percentage of 85 %. The potentiodynamic polarization curve indicates that the corrosion current densities of the BM, RS-TMAZ, AS-TMAZ and SZ are 0.89, 0.39, 0.85 and 0.36 μA/cm2, respectively, while the polarization impedances are 33.40, 51.42, 48.72 and 73.79 kΩ cm2, respectively. Combining the Nyquist and Bode plots analysis, the optimal electrochemical corrosion resistance is in SZ. The fine and homogeneous recrystallized grains in SZ significantly improve its electrochemical corrosion resistance. This is mainly ascribed to the increase in crystal defects as a result of the increase in grain boundaries, elevating the electron scattering. Simultaneously, the increase in high-energy state grain boundaries is beneficial to the rapid formation of a thicker passivation film.

Effect of Dynamic Recrystallization Mode on Texture Components and Hardness for Nano-SiC Particles Reinforced Aluminum Matrix Composites Prepared Via Friction Stir Processing

Effect of Dynamic Recrystallization Mode on Texture Components and Hardness for Nano-SiC Particles Reinforced Aluminum Matrix Composites Prepared Via Friction Stir Processing

Microstructural and nanoindentation study of spark plasma sintered high entropy alloy reinforced aluminium matrix composites

In this study, Spark Plasma Sintering (SPS) also known as a field-assisted technique was employed in the fabrication of high entropy alloy (HEA) reinforced aluminium matrix composites (using 5, 7 and 10 wt% HEA as the reinforcement in the composites); and conventional methods were employed to determine the relative density and microhardness; while nanoindentation technique was employed to determine the nanohardness, modulus of elasticity and nanoindentation depth of the sintered samples. Calculation Phase Diagram (CALPHAD) software, Thermocalc was employed in the prediction of the phases present in the HEA, while XRD was used in the confirmation of the phases. The phase analysis showed that BCC, FCC, and laves are the phases present in the fabricated HEA while the microstructural analysis showed that interdiffusion layers were formed; and atomic precipitation that resulted in the formation of new phases occurred during sintering. The microhardness, nanohardness, and modulus of elasticity of the sintered HEA-reinforced Al matrix composites increase with an increase in the wt% of HEA such that as little as 5 wt% HEA addition resulted in a 102.8 % increment in microhardness, while the densification and indentation depth were discovered to decrease with an increase in the wt% of HEA.”

Selection of groove dimension in the fabrication of particulate reinforced aluminium matrix composites using friction stir welding

Selecting groove dimensions has always been challenging for fabricating particulate reinforced aluminium matrix composites using friction stir welding. To address this, heat transfer physics coupled with the level set method was used to estimate material mixing between 6061-T6 Al-matrix and Al2O3 using the COMSOL Multiphysics tool. Groove dimensions of 2 mm width and depth resulted in the absence of volumetric/tunnel defects, nearly symmetric distribution, and minimal agglomeration of Al2O3 powder particles. This combination achieved an optimum trade-off between strength and ductility.

Achieving the strength-ductility synergy in ultra-fined grained CNT/2024Al composites via a low-temperature aging strategy

Synchronous enhancement of strength and ductility is a persistent challenge in the development and application of carbon nanotube (CNT)-reinforced aluminum matrix composites. This study proposed a low-temperature aging strategy to induce the nanoscale precipitates and evade the strength and ductility trade-off dilemma. The composites under various aging conditions were characterized in detail at the macro, micro, and nano scales. The precipitation behavior and strengthening mechanism were investigated systematically. Results indicated that the composite exhibited a better mechanical performance when aged at 100 °C. Compared to as-extruded composites, the yield and ultimate tensile strength of CNT/2024Al composites increased by 82.7 % and 64.8 %, respectively, whereas the elongation decreased by only 1.1 %. The results of microstructure and theoretical estimation suggested the dense nanoscale GP zones were primarily responsible for achieving the strength-ductility synergy. This present study on tailoring precipitate evolution could provide fundamental insights and references to enhance the mechanical properties of aluminum matrix composites.