Effects of CuO and SiO2 as reinforcement in aluminium (AA6061) chips hybrid nanocomposites using hot extrusion process

• Main Author: Hussein, Msebawi Muntadher Sabah Abdul
• Format: Thesis
• Language: English
• Published: 2022
• Subjects: Aluminum alloys; Composite materials
• Online Access: http://psasir.upm.edu.my/id/eprint/103946/1/MSEBAWI%20MUNTADHER%20-%20IR.pdf; http://psasir.upm.edu.my/id/eprint/103946/
• Institution: Universiti Putra Malaysia

Aluminium alloy AA6061 is widely used in various applications which generates a lot of waste in the form of aluminium chips that can be recycled back to the industry. The success of recycling AA6061 alloy chips is highly dependent on extrusion process parameters and the reinforcing materials to enhance its aluminium properties. However, incorporating copper oxide (CuO) and silica oxide (SiO2) nanoparticles into the aluminium matrix is a difficult task particularly due to their agglomeration as well as aggregations in the metal matrix nanoparticle reinforced composites (MMNCs). Furthermore, little quantities of these nanoparticles as reinforcements provides an effective improvement of the thermal, physical and mechanical properties of these nanocomposites. In addition, the literature lacks a comprehensive analysis of the relationship between the strength performance and hybrid composite materials. In this study, the nano silica oxide (SiO2) and nano copper oxide (CuO) were used for reinforcement purposes. Also, the research aimed at optimizing the influences of preheating temperature (PHT), preheating time (PHti), volume fraction of nano silica oxide (SiO2) and nano copper oxide (CuO) on the physical and mechanical properties of the aluminium AA6061 hybrid composite samples through hot extrusion treatment. Furthermore, the comparison and investigation analysis of physical, mechanical, and morphology between the single reinforced Al6061-SiO2 and Al6061-CuO nanocomposites were done. The three parameters mentioned above were varied in the range of 450 - 550 oC, 1 - 3 h, and 1 - 3 vol%. The optimum values of PHT, PHti, and VF to obtain the maximum tensile strength value was established to be at 541ºC, 2.25 h, as well as 1 vol.% of SiO2 and 2.13 vol.% CuO volume fraction respectively. On top of that, the response surface design (RSM) showed that the interaction between the reinforcements and PHT values contributed significantly to the strength and microhardness. While for the density values of the samples of both reinforcements, the PHti value was significant. On the other hand, the peak tensile strength value of 295.97 MPa was observed in the heat-treated extrudes which was improved to about 27% compared to the optimum tensile strength value of 232.66 MPa in nonheat-treated sample. At the same time, the Random Forest result value of 2.73% error for both validation and prediction showed that indicating the highly accurate results with no significant over-estimation or under-estimation of the targeted values. Finally, the Differential Scanning Calorimetry (DSC) profiles were employed to explain the weight loss, heat flow and crystallization temperature. Scanning Electron Microscope (SEM) and Field Emission Scanning Electron Microscope (FESEM) showed that the fractured surface in tensile samples differed in contours due to the proper distribution of stress in the composite samples. Lastly, the analysis of Atomic Force Microscopy (AFM) and XRay Diffraction (XRD) revealed that the distribution of CuO and SiO2 reinforced particles in specimens were slightly uniform. The results showed that the use of SiO2 and CuO as reinforcements in AA6061 recycling could avoid the possibility of particles aggregation in the recycled composites.