Volume 10 Issue 3 ( September 2023 )

In the present investigation, friction stir solid state process has been used to develop a functionally graded composite material reinforced with Si₃N₄ (Silicon nitride). The main aim of the current investigation is to develop a low density high strength silica reinforced aluminum based composite material develop by friction stir processing (FSP) process for aerospace and defence applications. FGM (Functionally Graded Composite Material) has been prepared by taking two dissimilar aluminium plates with Si₃N₄ as reinforcement content through friction stir processing (FSP) technique. To evaluate the mechanical properties of developed composite material tensile testing, hardness testing, thermal expansion and corrosion test have been performed. The tensile testing revealed the tensile strength, yield strength and percentage elongation of the developed composite material. Further the hardness testing estimated the scratch resistance. Microstructures results of Si ₃N₄ reinforced FGM composite showed the proper mixing of the ceramic particle in functionally graded materials (Al6063 and Al8011) at optimum FSP parameter. Effects of FSP parameters like Cutting fluid, Tool shape, Tool speed on tensile strength and hardness of FGM composite reinforced with Si₃N₄ ceramic particles were studied by using Taguchi’s technique L9 Orthogonal Array. The experimental results revealed that the highest tensile Strength is observed as 133.05 N/mm² at 1460 rpm for square shaped tool with kerosene as lubricant. Further lower values of tensile Strength i.e., 73.65 N/mm² at 920 rpm and 78 N/mm² at 2260 rpm are observed. Tensile Strength was good for kerosene with square tool shape and least for triangular and circular tool shape. The hardness of fabricated composite was good for circular tool shape and low speed (i.e., 920 rpm) but continuously decreases when tool shape is different. Hardness is good for brine solution at any tool speed but least for kerosene with any tool speed. The hardness of FGM composite was good for brine solution with any tool shape.

Keywords: Functionally graded composite; tool shape; rotational tool speed; cutting fluid; corrosion resistance.