CHARACTERIZATION OF TRIBOLOGICAL AND MECHANICAL PROPERTIES OF AA7050/Al2O3 COMPOSITES AT ELEVATED TEMPERATURE

In this research work, aerospace aluminum alloy AA7050 was reinforced through the stir casting route with Al2O3 with an average particle size of 5 mu m. Potassium titanium fluoride (K2TiF6) was added as flux to improve the wettability of reinforcement and matrix material. AA7050/Al2O3 composites of varying weight percentage (0, 2, 4, 6) were fabricated and machined to remove surface defects. Wear experiments were performed on composites by varying load, velocity, temperature, and weight percentage using a pin-on disc apparatus. The hardness and tensile tests were performed at elevated temperature. The results revealed that the addition of particles improves the wear resistance, owing to the formation of a mechanical mixed layer. The wear rate at 300 degrees C was 100% percent higher than the wear rate at 150 degrees C. The tensile strength and hardness of composites showed improvement, owing to the Orowan strengthening and Hall-Petch effects. The ANOVA table reveals that temperature was the most influential factor followed by the weight percentage of reinforcing particles. The parameters were optimized using the PROMTHEE approach. The results revealed that AA7050/4Al(2)O(3) at 150 degrees C and AA7050/2Al(2)O(3) at 300 degrees C possess better material properties.