University of Oulu

Newishy M, Jaskari M, Järvenpää A, Fujii H, Abdel-Aleem HA. Friction Stir Welding of Dissimilar Al 6061-T6 to AISI 316 Stainless Steel: Microstructure and Mechanical Properties. Materials. 2023; 16(11):4085.

Friction stir welding of dissimilar Al 6061-T6 to AISI 316 stainless steel : microstructure and mechanical properties

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Author: Newishy, Mohamed1; Jaskari, Matias2; Järvenpää, Antti2;
Organizations: 1Welding and NDT Department, Central Metallurgical Research & Development Institute CMRDI, Cairo 11421, Egypt
2Future Manufacturing Technologies (FMT) Research Group, Kerttu Saalasti Institute, University of Oulu, 85500 Nivala, Finland
3Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Osaka 567-0047, Ibaraki, Japan
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 10.6 MB)
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Language: English
Published: Multidisciplinary Digital Publishing Institute, 2023
Publish Date: 2023-09-22


The friction stir welding (FSW) process was recently developed to overcome the difficulty of welding non-ferrous alloys and steels. In this study, dissimilar butt joints between 6061-T6 aluminum alloy and AISI 316 stainless steel were welded by FSW using different processing parameters. The grain structure and precipitates at the different welded zones of the various joints were intensively characterized by the electron backscattering diffraction technique (EBSD). Subsequently, the FSWed joints were tensile tested to examine the mechanical strength compared with that of the base metals. The micro-indentation hardness measurements were conducted to reveal the mechanical responses of the different zones in the joint. The EBSD results of the microstructural evolution showed that a significant continuous dynamic recrystallization (CDRX) occurred in the stir zone (SZ) of the Al side, which was mainly composed of the weak metal, Al, and fragmentations of the steel. However, the steel underwent severe deformation and discontinuous dynamic recrystallization (DDRX). The FSW rotation speed increased the ultimate tensile strength (UTS) from 126 MPa at a rotation speed of 300 RPM to 162 MPa at a rotation speed of 500 RPM. The tensile failure occurred at the SZ on the Al side for all specimens. The impact of the microstructure change in the FSW zones was significantly pronounced in the micro-indentation hardness measurements. This was presumably attributed to the promotion of various strengthening mechanisms, such as grain refinement due to DRX (CDRX or DDRX), the appearance of intermetallic compounds, and strain hardening. The aluminum side underwent recrystallization as a result of the heat input in the SZ, but the stainless steel side did not experience recrystallization due to inadequate heat input, resulting in grain deformation instead.

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Series: Materials
ISSN: 1996-1944
ISSN-E: 1996-1944
ISSN-L: 1996-1944
Volume: 16
Issue: 11
Article number: 4085
DOI: 10.3390/ma16114085
Type of Publication: A1 Journal article – refereed
Field of Science: 214 Mechanical engineering
216 Materials engineering
Copyright information: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (