Date of Defense
17-11-2025 2:00 PM
Location
F1-1043
Document Type
Thesis Defense
Degree Name
Master of Science in Mechanical Engineering (MSME)
College
COE
Department
Mechanical and Aerospace Engineering
First Advisor
Dr. Jaber Abu Qudeiri
Keywords
AA6082 composites, ultrasonic assisted stir casting, hybrid nano composite, mechanical properties, microstructure.
Abstract
The utilization of aluminium alloys has increased rapidly in past decades due to the increasing demand for lightweight and high-performance materials. Among the popular aluminium alloys, AA6082 is widely favoured for its excellent combination of strength, corrosion resistance, and machinability. Most previous work, however, has concentrated on either on micro scale reinforcement or on single ceramic particles, leaving very few experimental studies on the use of hybrid nano reinforcement in AA6082. Therefore, to further enhance its mechanical properties without compromising its inherent advantages, hybrid metal matrix composites were developed using various nano particulates as reinforcements. In this current study, AA6082-based composites reinforced with nano-sized silicon carbide (SiC) and aluminium oxide (Al2O3) were fabricated using ultrasonic assisted stir casting under a controlled vacuum pressure. Hybrid reinforcements of nano SiC and Al₂O₃ were added at varying weight fractions of 0.5 wt.%, 0.75 wt.%, and 1 wt.% each by a two-step stir casting process. The fabricated composites were subjected to detailed microstructural characterization along with mechanical property evaluation through hardness, tensile and compression tests. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were utilized to examine the dispersion of reinforcements and the phase composition. Among the composites fabricated, AA6082- 1 wt.% SiC and Al₂O₃ hybrid nano metal matrix composite (NMMC) exhibited the highest improvement in Vickers hardness, ultimate tensile strength and compression strength, showing increases of 21.92%, 60.78%, and 30.50% respectively, compared to unreinforced AA6082 alloy. Such property enhancements arise from the uniform distribution of nano particles throughout the matrix, along with grain refinement seen under microstructural study, both of which enhanced the alloy’s ability to transfer load and resist deformation. The results demonstrated a significant improvement in microstructure and mechanical properties with increasing reinforcement content, confirming that AA6082 reinforced with nano SiC/Al₂O₃ is well suited for high performance applications, mainly in the automative and aerospace industry.
Included in
MICROSTRUCTURAL AND MECHANICAL CHARACTERIZATION OF AA6082 /SIC/AL2O3 HYBRID NANOCOMPOSITE FABRICATED BY ULTRASONIC-ASSISTED VACUUM DIE STIR CASTING
F1-1043
The utilization of aluminium alloys has increased rapidly in past decades due to the increasing demand for lightweight and high-performance materials. Among the popular aluminium alloys, AA6082 is widely favoured for its excellent combination of strength, corrosion resistance, and machinability. Most previous work, however, has concentrated on either on micro scale reinforcement or on single ceramic particles, leaving very few experimental studies on the use of hybrid nano reinforcement in AA6082. Therefore, to further enhance its mechanical properties without compromising its inherent advantages, hybrid metal matrix composites were developed using various nano particulates as reinforcements. In this current study, AA6082-based composites reinforced with nano-sized silicon carbide (SiC) and aluminium oxide (Al2O3) were fabricated using ultrasonic assisted stir casting under a controlled vacuum pressure. Hybrid reinforcements of nano SiC and Al₂O₃ were added at varying weight fractions of 0.5 wt.%, 0.75 wt.%, and 1 wt.% each by a two-step stir casting process. The fabricated composites were subjected to detailed microstructural characterization along with mechanical property evaluation through hardness, tensile and compression tests. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were utilized to examine the dispersion of reinforcements and the phase composition. Among the composites fabricated, AA6082- 1 wt.% SiC and Al₂O₃ hybrid nano metal matrix composite (NMMC) exhibited the highest improvement in Vickers hardness, ultimate tensile strength and compression strength, showing increases of 21.92%, 60.78%, and 30.50% respectively, compared to unreinforced AA6082 alloy. Such property enhancements arise from the uniform distribution of nano particles throughout the matrix, along with grain refinement seen under microstructural study, both of which enhanced the alloy’s ability to transfer load and resist deformation. The results demonstrated a significant improvement in microstructure and mechanical properties with increasing reinforcement content, confirming that AA6082 reinforced with nano SiC/Al₂O₃ is well suited for high performance applications, mainly in the automative and aerospace industry.