MCD Approach for Assessing the Optimal Operating Condition during Sliding Wear Characteristics of LM25/SiC AMCs Processed by an Improved Stir Casting Technique

Abstract

The Sliding wear behaviour of the improved stir cast LM25/SiC composite was investigated using a wear apparatus having pin-on-disc configuration. The tests were conducted at varying sliding speed, applied load and sliding distance based on the ‘Box-Behnken’ experimental design approach of Response Surface Methodology. The influence of process variables on wear rates, frictional heating and friction coefficient were analyzed by developing the regression model for the performance measures using RSM. The microstructural occurrences depicted strong interfacial bonding between the SiC particles and the matrix alloys due to entrapping of the SiC particles inside the primary Al dendrites. The Analysis of Variance (ANOVA) demonstrating the significance of each process variables on the developed regression model for all the performance characteristics. The linear and non-linear interaction effects of the process variables on the response measures were also identified using surface plots, further validated by experimental observations. A combined setting of process variables was identified, which thresholds the optimum values of combined performance measures using desirability based MOP. The confirmation experiments demonstrated that the errors were minimal (Wear rates 5.2%, 2.02% for frictional heating and 7.18% for COF) and fitted appropriately with developed quadratic surfaces for the response variables. The optimal processing condition was identified as Wear rate = 2.33 mm3/m; Temperature = 47 °C and COF = 0.167. The resulting surface was threshold a ‘Ra’ value of 1.66 μm, which was found to be lesser than that of the (Ra = 2.35 μm) surface produced during testing at initial parameter settings.