Dry and wet sliding, fatigue, creep and mechanical properties of AA-7475 metal matrix composite reinforced with Si2N2O from rice husk ash

Abstract

This study extensively explores the mechanical performance of AA7475 metal matrix composites reinforced with heat-treated Si2N2O sourced from rice husk ash. The specimens were meticulously fabricated using the stir casting method, ensuring a homogeneous dispersion of Si2N2O particles within the AA7475 matrix. The characterization of these specimens followed ASTM standards, encompassing evaluations of dry and wet sliding behavior, fatigue strength, creep resistance, and overall mechanical properties.Among the various specimens, the AAR3 designation emerged as the most promising, showcasing exceptional mechanical properties. AAR3 exhibited a remarkable tensile strength of 569 MPa, accompanied by a reduced elongation of 8%, yield strength of 264 MPa, and impact energy of 24.15 J. The increased rigidity attributed to the 6wt% Si2N2O particles in AAR3 also led to an improved hardness of 164.The trend of enhanced mechanical strength extended to fatigue properties, with AAR2 delivering a notable fatigue strength of 329 MPa. In terms of wear resistance, AAR3 stood out with impressive results, featuring a specific wear rate of 0.0075 mm³/Nm and a coefficient of friction (COF) of 0.44 for dry sliding wear. For wet sliding wear, AAR3 demonstrated a specific wear rate of 0.0047 mm³/Nm and a COF of 0.42.In the realm of creep properties, AAR3 exhibited reduced creep strain values of 0.01824, 0.0233, 0.0934, 0.2004, and 0.3505 for time intervals of 2000, 4000, 6000, 8000, and 10,000 s, respectively. These findings collectively emphasize the superior mechanical and tribological performance of AAR3, underlining the potential of heat-treated Si2N2O reinforcement for enhancing the properties of AA7475 metal matrix composites.