MECHANICAL AND SLIDING WEAR PERFORMANCE OF VACUUM-CAST AA7075-CO ALLOY COMPOSITES: PARAMETRIC OPTIMIZATION AND RANKING ANALYSIS

This research work reports on the mechanical and sliding wear performance analysis of vacuum-cast AA7075-Co (0-2 wt% @step of 0.5) alloy composites for gear application. The specimens were sized for their physical, mechanical, and sliding wear test standards. Wear tests were performed in lubricated conditions on a muti-specimen tribo-tester. The results show that reinforcement of cobalt particulates into the alloy matrix improves the mechanical properties and reduces the void content. The resultant composites have density ranges from 2.81 to 2.91 g/cc, voids content from (similar to 3.55 to 2.46%), hardness from 151.2 to 196 Hv, flexural strength from 341 to 498.2 MPa, compressive strength from 290 to 490 MPa, tensile strength from 235 to 394 MPa, and impact strength from 20 to 65.5 J. The specific wear rate shows a 25% improvement in performance with cobalt reinforcement relative to neat one. The Taguchi analysis with ANOVA reveals the following parametric order of normal load, sliding velocity, sliding distance, and filler content that actively controls the wear process of such composites. Further, Preference selection index ranking methods reveal that the composition having 2 wt% cobalt reinforcement tends to optimize overall performance metrics relative to others and has validated with subjective analysis.