Investigating the Mechanical and Tribological Effects of MoS2 Reinforcement in AZ91 Magnesium Alloy: A Comprehensive Experimental Study

Abstract

Magnesium is a lightweight metal with an impressive strength-to-weight ratio and is easy to use. This makes it highly desirable in the transportation industry, particularly for applications in which energy conservation and emissions reduction are key priorities. In recent decades, significant advancements have been made in magnesium-based composites, particularly with the introduction of magnesium matrix nanocomposites. These composites achieved enhanced strength through the incorporation of nanoparticles, while maintaining the original toughness of the matrix. This effectively bridges the gap between strength and flexibility, which is often observed in conventional magnesium composites. This breakthrough in the field of magnesium matrix nanocomposites (MMNCs) represents a new era of material development. However, Mg still faces challenges that hinder its widespread adoption. These include limited elasticity and ductility, susceptibility to creep and wear, and high corrosion rate. This study investigates the impact of the processing parameters on the friction stir processing (FSP) of AZ91 and a Mg alloy reinforced with MoS2. Notably, this experiment used the hole technique instead of the more common groove method. While the groove method dominates FSP applications, this project employs a 2 mm drill technique. The optimal processing conditions were as follows: rotation speed of 1100 rpm, travel speed of 15 mm/min, load of 10 kN, and use of a tungsten carbide tool material owing to its exceptional strength and durability. The surface microstructures and tensile strengths of the FSP-treated areas were analyzed further.