Frontiers in Materials (Mar 2022)
Tribological Performance Optimization of Mg-WC Nanocomposites in Dry Sliding: A Statistical Approach
Abstract
Magnesium nanocomposites reinforced with ceramic reinforcements have emerged as a superior structural material for automotive applications due to their excellent specific properties. In this context, the current study aims to scrutinize the performance of Mg-WC nanocomposites in tribological applications. The effect of various input parameters (wt.% of reinforcement, load, and speed) on output responses (wear and coefficient of friction) is scrutinized using response surface methodology. Mg-WC nanocomposites having varying weight percentages of WC are synthesized using ultrasonic treatment associated the stir-casting technique. Typical characterizations of as-cast nanocomposites are done using scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). SEM micrographs confirm homogeneous dissemination of fortified particles in the base matrix while EDS confirms elemental composition. Analysis of variance (ANOVA) study is conducted to discover significant parameters affecting tribological performance. Surface plots and contour plots for tribological responses are also examined to observe interaction effects. ANOVA on wear confirms that wt.% of WC and speed are the most significant parameters while the interaction between wt.% of WC and speed has a significant influence. For the coefficient of friction, all the input parameters are significant, and interaction between wt.% of WC and load is of utmost significance. Regression equations for response parameters are also developed. Additionally, a desirability approach is considered to investigate both single- and multiple-objective-optimization criterions of output parameters. The desirability function for both single- and multi-optimization remains 0.9778, suggesting the presence of all input parameters within the working limit. Predicted and experimental values of the optimal setting possess a close fit for the current study. Minimum wear is achieved when wt.% of WC is 1.73%, load is 40 N, and speed is 100 rpm. Minimum friction is obtained when wt.% of WC is 1.78%, load is 40 N, and speed is 100 rpm. The multi-optimization result shows that the minimum value of wear and friction is achievable when wt.% of WC is 1.73%, load is 40 N, and speed is 100 rpm. Finally, the worn surface of samples is examined to observe possible wear mechanisms.
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