Incorporation of Al2O3 powder for improvement of the mechanical and metallurgical properties of multi-passes friction stir welding of Al 2024

Farhang, Majid; Farahani, Mohammadreza; Nazari, Mohammad

Incorporation of Al2O3 powder for improvement of the mechanical and metallurgical properties of multi-passes friction stir welding of Al 2024

Document Type : Original Article

Authors

Majid Farhang ¹

Mohammadreza Farahani ²

Mohammad Nazari ³

¹ School of Mechanical Engineering, University of Tehran, Tehran

² School of mechanical Engineering, College of Engineering, University of Tehran

³ Faculty of Mechanical Engineering, Amirkabir University of Technology, Tehran, Iran

Abstract

The main aim of this experiment is to determine the mechanical and microstructural of using Nano powder of Al2O3 besides stir welding of Al2024-T6 in multi-pass welding. Nanoparticles welded nine specimens and one particle-free in 1400 rpm rotational speed and 16 mm/min traveling speed. A combination of volume percentage of powder (3%, 5%, and 7%) and three different multi continuous passes (1, 2, and 4) is applied for Nano-rich specimens. The microstructure of joint, micro hardness and ultimate tensile strength (UTS) of the welded joint has been studied. It was observed that by increasing the particle volume from 3% to 7% average grain size increased extremely to 37% and UTS to 10%, and in the staid situation of welding passes, average micro hardness has 10% increase in shoulder affected zone. The result showed that the specimen with 7% of Nanoparticles in two passes has the highest mechanical and metallurgical properties and has a significant decrease (55%) in average grain size compared with a particle-free specimen. Meanwhile, UTS and average micro hardness of the same specimen was about 11% and 48% more than particle free.

Keywords

Friction stir welding

tensile strength

metallurgical properties

multi-pass welding

Al2O3 Nano particle

Subjects