Microstructure evolution, mechanical properties, and fractography of AA7068/ Si3N4 nanocomposite fabricated thorough ultrasonic-assisted stir casting advanced with bottom pouring technique

Ceramic particulate embedded aluminum metal matrix nanocomposites (AMNCs) possess superior mechanical and surface properties and lightweight features. AMNCs are a suitable replacement of traditional material, i.e., steel, to make automotive parts. The current work deals with developing Si3N4 strengthened high strength AA7068 nanocomposites via novel ultrasonic-assisted stir casting method advanced with bottom pouring setup in the proportion of 0.5, 1.0, 1.5, and 2 wt.%. Planetary ball milling was performed on a mixture of AA7068 powder and Si3N4 (in the proportion of 3:1) before incorporation in aluminum alloy melt to avoid rejection of fine particles. Finite element scanning electron microscope (FESEM), Energy dispersive spectroscopy (EDS), X-Ray diffraction (XRD), and Elemental mapping techniques were used in the microstructural investigation. Significant grain refinement was observed with increasing reinforcing content, whereas agglomeration was found at higher weight %. Hardness, Tensile strength, ductility, porosity content, compressive strength, and impact energy were also examined of pure alloy and each composite. Improvement of 72.71%, 50.07%, and 27.41 % was noticed in hardness value, tensile strength, and compressive strength, respectively, at 1.5 weight % compared to base alloy because of various strengthening mechanisms. These properties are decreased at 2wt.% due to severe agglomeration. In contrast, nanocomposite's ductility and impact strength continuously decrease compared to monolithic AA7068. Fracture analysis shows the ductile and mixed failure mode in alloy and nanocomposites.

Machinability study of Aluminium 6082 reinforced with boron carbide and titanium by stir casting method using Abrasive water jet machining process

Aluminium Metal Matrix Composite (AMMC) has broad uses in the medical, aerospace, and automobile industries, which have long sought lightweight materials with superior designs and improved properties to improve performance. This analysis has aimed to prepare an AMMC to investigate its machining and mechanical properties. The AMMC is produced using a stir casting process by reinforcing boron carbide and titanium with aluminium 6082. The material's mechanical properties are studied by using wear test, hardness test, and corrosion test. The wear rate increases when the load increases by varying the load and time with speed as a constant. It is found that the hardness of a material is increased due to titanium and boron carbide as the reinforcement particle in the fabricated AMMC. Using the pitting corrosion technique, the corrosion occurs on the AMMC under the estimated time at room temperature. In order to illustrate the machining characteristics of the aluminium metal matrix composite, an abrasive water jet machining process has been used. The experiments use L9 orthogonal Array using Taguchi's method and ANOVA analysis. The input parameters considered are Traverse rate, Stand-off distance, and Nozzle diameter. To find the optimum value of circularity, cylindricity, and surface roughness by varied input parameters. The respective graphs are also plotted. Scanning electron microscopic analysis was performed on the wear-tested specimen and machining surface of the material to determine the distribution of reinforced material and investigate the material's fracture mechanism. It is found that wear tracks, voids, delamination, micro pits, embedded garnet abrasive particles are located on the machined surface of the AMMC.

Development of Al-SiC composite material from rice husk and its parametric assessment

In this research work, the development of Al-SiC composite material from rice husk and its parametric assessment is done using a CNC milling machine. They are further surface characterized, and mechanical properties such as BET surface area, SEM-EDX, and XRD, fracture toughness, tensile, and bending strength are studied. The machinability of the components is investigated for selected values of input-output parameters. Three castings, each with different particulate reinforcement combinations, are made with aluminum alloy (6061) using the stir casting method. BET surface area of extracted silica and Al-SiC composite material was found 374 m2/g and 150 m2/g, respectively. From results of BET surface area revealed that silica obtained from rice husk is more heterogeneous with a large surface area. A heterogeneous surface with larger pores was found through SEM images. XRD diffraction peaks show changes of amorphous silica into crystallinity in the composite material. The results also indicate that fracture toughness is very good at low temperatures and good machinability on CNC milling machines makes it suitable for aerospace applications.

Investigation on Mechanical and Wear Behaviors of LM6 Aluminium Alloy-Based Hybrid Metal Matrix Composites Using Stir Casting Process

In this investigation, aluminium-silicon-based alloy (LM6) with the addition of (0, 2.5, 5, and 10%) copper-coated short steel fiber and 5% boron carbide (B4C) element-strengthened composites was fabricated by the stir casting method. Mechanical properties and tribological behaviors of LM6-based hybrid composites were investigated, and microstructures of different castings were examined by an image analyzer. The test was conducted at different loads (10, 20, 30, and 40 N) and different sliding spaces (500, 1000, 1500, and 2000 m), respectively. The results revealed that the sample loaded with 10% of reinforcement recorded the highest tensile strength of 231 MPa. On the other hand, the hardness value increased from 71 to 144 BHN, when 15% of reinforcement was added to the sample. It was also noted that 10% copper-coated steel fiber improved wear resistance up to 50% when compared to LM6. A field emission scanning electron microscope was employed to observe the morphology of the worn surfaces of composites at different sliding distances and load conditions. The hybrid composite revealed that the combination of both short steel fibers and reinforcement of ceramic particles enhanced the mechanical properties, obtaining superior wear resistance.

Analysis of Mechanical Behavior of Al6061 Composites Reinforced with Titanium Dioxide

Aluminum alloys are used low density good mechanical properties, better wear resistance as compared to predictable metals and their alloys. The industries are continuing in demand to develop light weight material, inexpensive and strong material which has led to the growth of aluminum alloy metal matrix composites. The aluminum based metal matrix composites have been moulded using TiO2 as reinforcement materials using the stir casting process. The hardness and tensile strength have been calculated addition to the TiO2 in Aluminium matrix improves the hardness of the material. The tensile strength and hardness increases above 4% of titanium oxide particles in the matrix.

Fabrication and characterization of SiC-reinforced Al-4032 metal matrix composites

Aluminium metal matrix composites (AMCs) have become quite popular for light weight, low cost, and good workability. The present work reports the impact of silicon carbide (SiC) reinforcement on the physical, microstructural, and mechanical characteristics of Al-4032/SiC composites with 4, 6, 8% of SiC (particle size 54μm) fabricated through bottom pouring stir casting. Density and porosity measurements of all three AMCs have been performed using the rule of mixture. The microstructure of the AMC samples has been analyzed using an optical microscope (OM), x-ray diffraction analysis (XRD), and scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS). The mechanical properties, in terms of the ultimate tensile strength (UTS), elongation, micro-hardness, and impact toughness of the AMCs have also been obtained according to American society for testing and materials (ASTM) standards. A maximum 1.52% increase in theoretical density, while a maximum 2.92% decrease in experimental density has been recorded for 8% reinforcement. The UTS, microhardness, and impact toughness of the AMC have been found to improve significantly owing to the addition of ceramic particles. The uniform distribution of SiC particles all over base Al-4032 matrix material has been noticed by SEM and OM for AMCs up to 6% reinforcement.

Contriving and Assessment of Magnesium Alloy Composites Augmented with Boron Carbide VIA Liquid Metallurgy Route

In modern engineering low-density composites plays a vital role of which magnesium alloys are very effective due to its high strength with better corrosion resistance and neat cast ability. In this work a micron sized Boron carbide ceramic (B4C) of about 100 microns is diffused as a reinforcement with AZ91 for preparing a magnesium metal matrix composite (MMMC) through stir casting route. A modified pit furnace setup is used for doing stir casting with varying volume fractions of 0％ and 3% of boron carbide for doing the composites. Furthermore mechanical and metallurgical properties like Tensile test is made through universal testing machine, Micro-hardness through Vickers hardness tester and Micro structure through Optical Microscopy is done for investigation.

Production and Assessment of AZ91 Reinforced with Nano SiC through Stir Casting Process

Magnesium, a light weight alloy used in multiple engineering industrial applications because of its good Physical, Chemical and Thermal characteristics. Magnesium composites play an important role in partial or entire replacement of numerous alloys.This current work deals with Nano silicon carbide of about 100nm was incorporated with AZ91magnesium alloy through liquid state composite processing. Two samples are made using 0% Nano SiC and 3% Nano SiC and are characterized through tensile test in Universal Testing Machine, Micro hardness test in Vickers hardness tester and Microstructure in Optical Microscopy. From the study it was clear that there is a peak increase in hardness of about 36% when compared to as casted AZ91.