Synthesis, microstructural analysis, and wear optimization of Al6061–Si3N4 composites via stir casting for automotive and aerospace applications

This study focuses on the synthesis and characterization of Al6061-Silicon Nitride (Si₂N₄) composites fabricated using the stir casting technique. The primary objectives were to analyze the microstructure, investigate wear behavior, and optimize wear parameters through the Taguchi statistical approach. Al6061 was chosen as the matrix material due to its lightweight nature, corrosion resistance, and favorable mechanical properties, while 6 wt.% of high-hardness ceramic Si₂N₄ served as the reinforcement. The composite was produced via liquid metallurgy to ensure uniform particle distribution and strong interfacial bonding. Scanning Electron Microscopy confirmed homogeneous dispersion of Si₂N₄ particles within the matrix. Wear tests were conducted using a pin-on-disc tribometer under varying conditions of load, sliding distance, and speed. Results revealed that the Al6061-6% Si₂N₄ composite exhibited significantly lower wear loss compared to the base alloy. The wear of Al6061 alloy and Al6061-6% Silicon Nitride composite at 10 N load, 450 rpm speed and 300 m sliding distance are 91 microns and 115 microns respectively. There is a decrease in wear that is equal to 21% from Al6061 alloy to Al6061-6%Si₃N₄ composite. Taguchi L₂₇ orthogonal array was used to optimize the process parameters, which showed that Load is the most significant contributing factor i.e., 63.21% followed by Speed 30.38% and Sliding Distance 1.20%. The confirmation tests were carried out for the optimal parameters and the outcomes showed that the error falls in an acceptable range and it is equal to 2.54%. The produced composite resulted in the improvement of microstructure and enhanced tribological properties. These results indicate that the Al6061-Si₃N₄ composites are potential materials for automotive, aerospace and wear-resistant engineering parts.