Crack Repairing of Aluminum Alloy 2024 by Reinforcement of Al2O3 and B4C Particles using Friction Stir Processing

Abstract

Aluminum alloys welding using conventional welding methods is not a good choice as the strength of the part decreases and the number of defects increases. Therefore, these welding techniques are not incorporated for the repairment of aluminum structures where cracks are generated through some reasons. Instead the mechanical methods used to repair the cracks in aluminum alloys like adding a complete patch over the crack which does not give the same properties and is not feasible in the minor tolerances areas and also cause an increase in the overall weight. Friction Stir Welding is a joining and processing technique which operates below the melting point of the part. FSW/FSP is frequently used for joining/processing of Al alloys from the last decade because of its promising results as compared to conventional techniques. Joint efficiencies of aluminum alloys using FSW is further enhanced using nano/micro reinforcements. The distribution of the reinforcements also plays a vital role in the strengthening of the joined part. The objective of this research was to repair the crack in aluminum alloy 2024 with the help of FSW and to check the properties of the base metal after the crack repaired without reinforcements and with the reinforcements of Al2O3 and B4C along the crack. The study also indicates a brief description about the welding parameters, process conditions and the equipment used for processing. The mechanical properties of the prepared samples were examined using micro-hardness and tensile testing whereas microscopic analysis were performed for metallurgical investigations and X-ray diffraction analysis for crystallinity and intermetallic studies. Field Emission Scanning Electron Microscopy was performed to investigate detailed structural analysis and particles distribution in the aluminum matrix. The crack in the Al-2024 is effectively repaired using FSP. The reinforced samples showed improved strength as compared to non-reinforced ones. There is no formation of intermetallic and the samples show particles distribution in the aluminum matrix. This study has potential applications in aerospace, marine and automobile industries.