Effect of WS2 Nanotubes on the Mechanical and Wear Behaviors of AZ31 Stir Casted Magnesium Metal Matrix Composites

Abstract

In this study, the AZ31 magnesium alloy was reinforced with tungsten disulfide (WS2) nanotubes to fabricate the nanocomposite using the stir casting method. The microstructural analysis, mechanical and wear behaviors were investigated with the effect of WS2 on the AZ31 alloy. Scanning electron microscopy (SEM) was used to conduct the microstructural analysis. The microstructures are revealed to incorporate the aluminum content with the WS2 nanotube, disclose the presence of the secondary phase, which was increased compared with the AZ31 alloy and was detected by energy dispersive spectroscopy (EDS). The mechanical properties of hardness and yield strength (YS) were significantly improved with the addition of WS2 nanotubes. This is mainly due to the strengthening mechanisms of Orowan, the coefficient of thermal expansion (CTE) mismatch and the load transfer mechanism. The theoretical YS was calculated and compared with the experimental results. However, the ultimate tensile strength (UTS) and the fracture strain were decreased with the addition of reinforcement which might be owing to the clustering of nanotubes. Finally, the wear behavior of the wear weight loss and depth of cut was investigated. This test revealed that the addition of WS2 nanotubes reduced the weight loss and depth of the material cutting that was mainly due to the presence of hard WS2 nanotubes.

Recent advances in mechanical properties of Mg matrix composites: a review

“…Compared to other methods, SC is commercially accepted as an economical method and is suitable for high production speed, production of complex-shaped and large parts. 45,84,85 In addition, reinforcement can be added up to 30% volume content. The selection of the ideal process parameter is very important for homogeneous particle distribution.…”

“…5,41,42 In the literature, there are recent studies on Mg matrix composite produced by SC. [43][44][45][46][47][48][49][50][51][52][53][54] Fang et al 43 produced AZ31/Al 3 Fe composites by SC followed by hot rolling. The hot rolled samples were homogenised at 693 K for 12 h. Cross-rolling was performed at 673 K, and the samples were cooled in the air when the total plastic deformation was 70%.…”

“…The increase in hardness is attributed to hard particles greatly restricting local plastic deformation during indentation. 44,45,53,124,125 Subramani et al 46 attributed the increase in hardness to grain refinement, secondary phase particles, and strain hardening. Yellapragada et al 49 reported that the reinforcement particles increased the hardness by increasing the load-carrying capacity, but when the reinforcement content exceeded the critical level, the hardness decreased due to particle 43 agglomeration.…”

“…[126][127][128][129][130][131] The decrease in strength at high reinforcement content is attributed to the agglomeration of the particles, increasing the porosity, weakening interfacial bonding, and acting as a stress concentrator of the particles. 44,45,70…”

“…Different researchers reported that the CTE of mismatch contributed to the increase in strength of Mg matrix composites. 44,45,[60][61][62] Borodianskiy et al 44 reported that one of the mechanisms of strengthening of AZ31/SiC composites is CTE mismatch. The CTE of AZ31 and SiC were 25 × 10 −6 and 6.6 × 10 −6 K −1 , respectively.…”