Design of Functionally Graded Composites through Friction Stir Processing

An Investigation was conducted to produce Aluminium based Functionally graded material (FGM) composites by Friction stir processing (FSP). A reinforcement strategy featuring the use of Alumina and TiC reinforcements was investigated, where holes were drilled in an Aluminium plate, filled with reinforcements and stirred using FSP. A mathematical model was formulated for positioning of holes in such a manner that the composition of the reinforcements varies from maximum to minimum over a given length. Samples were subjected to various number of FSP passes from one to three with 100% overlap and its influence on particle distribution and homogeneity was studied using Scanning electron microscopy (SEM) at cross sections parallel to the tool traverse direction. A progressive gradient in hardness values was observed for the surface composites at all the passes.