Study of friction stir processing (FSP) and high pressure torsion (HPT) and their effect on mechanical properties

Abstract

AbstractProduction of Bulk Nano-structured Materials (BNM) using Severe Plastic Deformation (SPD) is currently being pursued by researchers all around the world. Recently FSP has gained prominence on account of its ability to create BNM in the processed specimen. In the present study an improvised Vertical Milling Machine is designed that can perform FSP on thin metallic sheets. Al6061 sheets of 2mm thick are subjected to FSP and its effect on microstructure is studied. It is observed that very fine grains are formed in these sheets. Further effect of FSP on hardness is studied with the help of micro hardness tester. It is found that the hardness has increased by 50% on the processed AL6061 sheets on account of FSP. The study clearly brings out the advantage of severe plastic deformation caused on account of FSP and HPT and is a step forward in developing Bulk Nano-structured Materials (BNM) materials in future. Another important SPD process is High Pressure Torsion (HPT). In this work Finite element (FE) modeling of HPT of a circular disc of commercially pure aluminum (Al99) is also attempted to illustrate the advantage using FEM in evaluating equivalent strain and hardness numerically prior to experimentation