Pre-weld friction stir processing mitigates hot cracking and strengthens AA6061 fusion welds

Abstract Hot cracking remains a significant challenge in the fusion welding of high-strength aluminum alloys, particularly AA6061, which is highly susceptible to solidification cracking in the fusion zone (FZ). This study investigates the efficacy of friction stir processing (FSP) as a pre-weld trea...

Full description

Saved in:
Bibliographic Details
Main Authors: Ali Jalili, Ali Ghasemi, Mehran Torabi Kafshgari, Swee Leong Sing, Majid Pouranvari
Format: Article
Language:English
Published: Nature Portfolio 2025-05-01
Series:Scientific Reports
Subjects:
Online Access:https://doi.org/10.1038/s41598-025-99424-8
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1850190716880289792
author Ali Jalili
Ali Ghasemi
Mehran Torabi Kafshgari
Swee Leong Sing
Majid Pouranvari
author_facet Ali Jalili
Ali Ghasemi
Mehran Torabi Kafshgari
Swee Leong Sing
Majid Pouranvari
author_sort Ali Jalili
collection DOAJ
description Abstract Hot cracking remains a significant challenge in the fusion welding of high-strength aluminum alloys, particularly AA6061, which is highly susceptible to solidification cracking in the fusion zone (FZ). This study investigates the efficacy of friction stir processing (FSP) as a pre-weld treatment to enhance the weldability of AA6061 by engineering the base metal microstructure. We demonstrate that FSP transforms AA6061 from a material highly prone to solidification cracking into one with remarkable crack resistance during fusion welding. By applying multi-pass FSP to AA6061-T6, we achieved a base metal with ultra-fine grains, which facilitated the epitaxial growth of fine grains during subsequent fusion welding. The refined grain structure in the FZ, combined with reduced dendrite arm spacing, significantly mitigated solidification cracking by improving grain coalescence and strain accommodation during solidification. Post-weld T6 heat treatment resulted in a joint efficiency of 0.95 in tensile strength, outperforming conventional fusion welding and friction stir welding. This work highlights the potential of FSP as a pre-weld treatment to convert crack-prone aluminum alloys into viable candidates for high-integrity, lightweight structural applications.
format Article
id doaj-art-3c9fb2a7398d47c48ed1a40d16c35de6
institution OA Journals
issn 2045-2322
language English
publishDate 2025-05-01
publisher Nature Portfolio
record_format Article
series Scientific Reports
spelling doaj-art-3c9fb2a7398d47c48ed1a40d16c35de62025-08-20T02:15:11ZengNature PortfolioScientific Reports2045-23222025-05-0115111010.1038/s41598-025-99424-8Pre-weld friction stir processing mitigates hot cracking and strengthens AA6061 fusion weldsAli Jalili0Ali Ghasemi1Mehran Torabi Kafshgari2Swee Leong Sing3Majid Pouranvari4Department of Materials Science and Engineering, Sharif University of TechnologyDepartment of Mechanical Engineering, College of Design and Engineering, National University of SingaporeDepartment of Materials Science and Engineering, Sharif University of TechnologyDepartment of Mechanical Engineering, College of Design and Engineering, National University of SingaporeDepartment of Materials Science and Engineering, Sharif University of TechnologyAbstract Hot cracking remains a significant challenge in the fusion welding of high-strength aluminum alloys, particularly AA6061, which is highly susceptible to solidification cracking in the fusion zone (FZ). This study investigates the efficacy of friction stir processing (FSP) as a pre-weld treatment to enhance the weldability of AA6061 by engineering the base metal microstructure. We demonstrate that FSP transforms AA6061 from a material highly prone to solidification cracking into one with remarkable crack resistance during fusion welding. By applying multi-pass FSP to AA6061-T6, we achieved a base metal with ultra-fine grains, which facilitated the epitaxial growth of fine grains during subsequent fusion welding. The refined grain structure in the FZ, combined with reduced dendrite arm spacing, significantly mitigated solidification cracking by improving grain coalescence and strain accommodation during solidification. Post-weld T6 heat treatment resulted in a joint efficiency of 0.95 in tensile strength, outperforming conventional fusion welding and friction stir welding. This work highlights the potential of FSP as a pre-weld treatment to convert crack-prone aluminum alloys into viable candidates for high-integrity, lightweight structural applications.https://doi.org/10.1038/s41598-025-99424-8Solidification crackingLiquation crackingFriction stir processingAA6061 aluminum alloy
spellingShingle Ali Jalili
Ali Ghasemi
Mehran Torabi Kafshgari
Swee Leong Sing
Majid Pouranvari
Pre-weld friction stir processing mitigates hot cracking and strengthens AA6061 fusion welds
Scientific Reports
Solidification cracking
Liquation cracking
Friction stir processing
AA6061 aluminum alloy
title Pre-weld friction stir processing mitigates hot cracking and strengthens AA6061 fusion welds
title_full Pre-weld friction stir processing mitigates hot cracking and strengthens AA6061 fusion welds
title_fullStr Pre-weld friction stir processing mitigates hot cracking and strengthens AA6061 fusion welds
title_full_unstemmed Pre-weld friction stir processing mitigates hot cracking and strengthens AA6061 fusion welds
title_short Pre-weld friction stir processing mitigates hot cracking and strengthens AA6061 fusion welds
title_sort pre weld friction stir processing mitigates hot cracking and strengthens aa6061 fusion welds
topic Solidification cracking
Liquation cracking
Friction stir processing
AA6061 aluminum alloy
url https://doi.org/10.1038/s41598-025-99424-8
work_keys_str_mv AT alijalili preweldfrictionstirprocessingmitigateshotcrackingandstrengthensaa6061fusionwelds
AT alighasemi preweldfrictionstirprocessingmitigateshotcrackingandstrengthensaa6061fusionwelds
AT mehrantorabikafshgari preweldfrictionstirprocessingmitigateshotcrackingandstrengthensaa6061fusionwelds
AT sweeleongsing preweldfrictionstirprocessingmitigateshotcrackingandstrengthensaa6061fusionwelds
AT majidpouranvari preweldfrictionstirprocessingmitigateshotcrackingandstrengthensaa6061fusionwelds