Microstructural, Tribology and Corrosion Properties of Optimized Fe3O4-SiC Reinforced Aluminum Matrix Hybrid Nano Filler Composite Fabricated through Powder Metallurgy Method

Effect of Milling Time and Reinforcement Volume Fraction on Microstructure and Mechanical Properties of SiCp-Reinforced AA2017 Composite Powder Produced by High-Energy Ball Milling

The influence of milling time and volume fraction of reinforcement on the morphology, microstructure, and mechanical behaviors of SiCp-reinforced AA2017 composite powder produced by high-energy ball milling (HEBM) was investigated. AA2017 + SiCp composite powder with different amounts of SiC particles (5, 10, and 15 vol%) was successfully prepared from gas-atomized AA2017 aluminum alloy powder with a particle size of <100 μm and silicon carbide (SiC) powder particles with an average particle size of <1 μm. An optical microscope (OM), X-ray diffraction (XRD), and scanning electron microscope (SEM) were utilized to characterize the microstructure of the milled composite powder at different milling periods. The results indicated that the SiC particles were homogeneously distributed in the AA2017 matrix after 5 h of HEBM time. The morphology of the particles transformed from a laminar to a nearly spherical shape, and the size of the milled powder particles reduced with increasing the content of SiC particles. The XRD analysis was carried out to characterize the phase constituents, crystallite size, and lattice strain of the composite powders at different milling periods. It was found that with increasing milling time and SiC volume fraction, the crystallite size of the aluminum alloy matrix decreased while the lattice strain increased. The average crystallite sizes were reduced from >300 nm to 68 nm, 64 nm, and 64 nm after 5 h of milling, corresponding to SiC contents of 5, 10, and 15 vol%, respectively. As a result, the lattice strain increased from 0.15% to 0.5%, which is due to significant plastic deformation during the ball milling process. XRD results showed a rapid decrease in crystallite size during the early milling phase, and the minimum grain size was achieved at a higher volume fraction of SiC particles. Microhardness tests revealed that the milling time has a greater influence on the hardness than the amount of SiC reinforcements. Therefore, the composite powder milled for 5 h showed an average microhardness three times higher than that of the unmilled powder particles.

Revealing the Influence of SiC Particle Size on the Hot Workability of SiCp/6013 Aluminum Matrix Composites

SiC particle (SiCp) size has been found to significantly influence the hot workability of particle-reinforced aluminum matrix composites (AMC). In this work, therefore, three types of SiCp/6013 composites with different SiCp sizes (0.7, 5 and 15 μm) were prepared and then subjected to isothermal hot compression tests. In addition, constitutive analysis, processing maps and microstructural characterizations were used to reveal the influence of SiCp size on the hot workability of SiCp/6013 composite. The results showed that the values of hot deformation activation energy Q increased with decreasing SiCp size. Specifically, at lower temperatures (e.g., 350 and 400 °C), the highest peak stress was shown in the AMC with SiCp size of 0.7 μm (AMC-0.7), while in the AMC with SiCp size of 5 μm (AMC-5) at higher temperatures (e.g., 450 and 500 °C). This is because a finer SiCp size would lead to stronger dislocation pinning and grain refinement strengthening effects, and such effects would be weakened at higher temperatures. Further, dynamic softening mechanisms were found to transform from dynamic recovery to dynamic recrystallization with increasing SiCp size, and the dynamic recrystallization occurred more easily at higher temperatures and lower strain rates. Consequently, the instability zones of the composites are all mainly located in the deformation region with lower temperature and higher strain rate, and smaller SiCp results in larger instability zones.

The Reaction Products of the Al-Nb-B2O3-CuO System in an Al 6063 Alloy Melt and Their Influence on the Alloy's Structure and Characteristics

To meet aero-engine aluminum skirt requirements, an experiment was carried out using Al-Nb-B₂O₃-CuO as the reaction system and a 6063 aluminum alloy melt as the reaction medium for a contact reaction, and 6063 aluminum matrix composites containing in situ particles were prepared with the near-liquid-phase line-casting method after the reaction was completed. The effects of the reactant molar ratio and the preheating temperature on the in situ reaction process and products were explored in order to determine the influence of in situ-reaction-product features on the organization and the qualities of the composites. Thermodynamic calculations, DSC analysis, and experiments revealed that the reaction could continue when the molar ratio of the reactants of Al-Nb-B₂O₃-CuO was 6:1:1:1.5. A kinetic study revealed that the Al thermal reaction in the system produced Al₂O₃ and [B], and the [B] atoms interacted with Nb to generate NbB₂. With increasing temperature, the interaction between the Nb and the AlB₂ produced hexagonal NbB₂ particles with an average longitudinal size of 1 μm and subspherical Al₂O₃ particles with an average longitudinal size of 0.2 μm. The microstructure of the composites was reasonably fine, with an estimated equiaxed crystal size of around 22 μm, a tensile strength of 170 MPa, a yield strength of 135 MPa, an elongation of 13.4%, and a fracture energy of 17.05 × 10⁵ KJ/m³, with a content of 2.3 wt% complex-phase particles. When compared to the matrix alloy without addition, the NbB₂ and Al₂O₃ particles produced by the in situ reaction had a significant refinement effect on the microstructure of the alloy, and the plasticity of the composite in the as-cast state was improved while maintaining higher strength and better overall mechanical properties, allowing for industrial mass production.

Magnetic, Electrical, and Physical Properties Evolution in Fe3O4 Nanofiller Reinforced Aluminium Matrix Composite Produced by Powder Metallurgy Method

An investigation into the addition of different weight percentages of Fe₃O₄ nanoparticles to find the optimum wt.% and its effect on the microstructure, thermal, magnetic, and electrical properties of aluminum matrix composite was conducted using the powder metallurgy method. The purpose of this research was to develop magnetic properties in aluminum. Based on the obtained results, the value of density, hardness, and saturation magnetization (Ms) from 2.33 g/cm³, 43 HV and 2.49 emu/g for Al-10 Fe₃O₄ reached a maximum value of 3.29 g/cm³, 47 HV and 13.06 emu/g for the Al-35 Fe₃O₄ which showed an improvement of 41.2%, 9.3%, and 424.5%, respectively. The maximum and minimum coercivity (Hc) was 231.87 G for Al-10 Fe₃O₄ and 142.34 G for Al-35 Fe₃O₄. Moreover, the thermal conductivity and electrical resistivity at a high weight percentage (35wt.%) were 159 w/mK, 9.9 × 10^-4 Ω·m, and the highest compressive strength was 133 Mpa.

Microstructural Analysis and Mechanical Properties of a Hybrid Al/Fe2O3/Ag Nano-Composite

This work aims to define the microstructure and to study the mechanical properties of an Al matrix incorporated with various amounts of Fe2O3 (3, 6, 9, 12 and 15 wt.%) with a constant amount of Ag at 1 wt.%. Al/Fe2O3 + Ag hybrid nano-composite samples are manufactured using powder metallurgy. An aluminum matrix is considered an important alloy, owing to its properties such as being lightweight, strong and corrosion and wear resistant, which enable it to be used in many applications, such as electronics, aerospace and automotive purposes. Various examinations have been performed for the samples of this work, such as Field Emission Scanning Electron Microscopy (FESEM) and X-ray Diffraction (XRD) analysis to estimate the microstructure and phases of manufactured nano-composites. Mechanical testing is also carried out, such as micro-hardness testing, compressive testing and wear testing, to estimate the mechanical properties of the hybrid nano-composites. The results of FESEM and XRD demonstrate that Fe2O3 and Ag nanoparticles are uniformly distributed and dispersed into the Al matrix, whereas the mechanical tests show that enhancement t micro-hardness, compressive strength of 12 wt.% Fe2O3 + 1Ag and wear rate decrease to a minimum value of 12 wt.% of Fe2O3 + 1Ag.