Mechanical Characterization of AA357 Metal Matrix Composite with Reinforcement of Si3N4

The engineering sector researchers are always searching for new materials for their challenging applications. The aluminum alloy (AA) 357 plays a critical role in applications like automotive and aerospace because of its exceptional characteristics such as toughness, fatigue resistance, and more importantly strength-to-weight ratio, but it suffers from poor wear resistance. However, the research community is looking for enhancement in wear resistance at various loads. This research deals with AA357-Si3N4 nanocomposites fabricated through the induction stir casting method and evaluation of properties in comparison with AA357 matrix. The Si3N4 nanoparticulates were selected as reinforcement and added 0.5 to 3.0 wt.% in the steps of 0.5 wt.%. The influence of Si3N4 nano reinforcement content on hardness, strength, and wear resistance of AA357-Si3N4 nanocomposites investigative work was conducted as per ASTM standards. The studies of microstructures of AA357-Si3N4 nanocomposites were performed using an optical microscope to analyze grain structure and a scanning electron microscope (SEM) to examine particle distribution. The density, hardness, and ultimate tensile strength (UTS), in addition to morphological studies of fractured surfaces and energy dispersive spectroscopy for nanocomposites elemental study. As per ASTM G99, Standard Test Method for Wear Testing with a Pin-on-Disk Apparatus, standards, pin-on-disc equipment was used to examine tribological properties of AA357-Si3N4 nanocomposites and SEM pictures of worn nanocomposites surfaces analyzed extensively. By going through the experimental outcomes, it is realized that with increase in nano reinforcement in matrix AA357, the properties such as density, resistance to indentation/hardness, and UTS increased at the expense of percentage elongation. The pin-on-disc tribometer experimental results indicate that the fabricated AA357-Si3N4 nanocomposites have higher wear resistance.