{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,20]],"date-time":"2025-11-20T11:16:23Z","timestamp":1763637383151,"version":"3.45.0"},"reference-count":33,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2025,11,20]],"date-time":"2025-11-20T00:00:00Z","timestamp":1763596800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JMMP"],"abstract":"<jats:p>Joining dissimilar metals, such as aluminum and steel, presents an attractive option for creating lightweight yet durable structures. However, challenges arise from the formation of brittle intermetallic compounds (IMCs) at the interface of dissimilar joints, which significantly impact joint strength under load and often lead to brittle failure. This research elaborates on how an S-shaped Al\/Steel interface made by a modified friction stir welding (FSW) process mitigates the detrimental effect of IMC thickening on joint strength. This study aims to explore the effects of various post-weld heat treatments on steel and aluminum joints produced through FSW (100\u2013400 \u00b0C for 30\u201390 min). Al\/steel FSW joints were characterized by SEM\/EDS for interface microstructure and composition, microhardness mapping, tensile testing, and fractography. Any post-weld heat treatment above the temperature of 100 \u00b0C caused a drop in joint strength from 2400 N to 1800 N due to the elimination of protrusions in the IMC layer. Further post-weld heat treatment had a negligible effect on the joint strength due to an S-shaped interface. A finite element simulation using a cohesive model for the joint interface is used to study the fracture mechanism of the joint. Both experimental observations and simulation results suggest that the portion of the S-shaped interface perpendicular to the loading direction acts as an initiation site of fracture and fails in a brittle manner. The top and bottom of the interface, which are inclined to the loading direction, fail in a ductile manner with noticeable plastic deformation in the steel adjacent to the interface. The proposed method for FSW of aluminum to steel significantly improves joint durability at elevated temperatures, particularly up to 400 \u00b0C.<\/jats:p>","DOI":"10.3390\/jmmp9110381","type":"journal-article","created":{"date-parts":[[2025,11,20]],"date-time":"2025-11-20T10:30:59Z","timestamp":1763634659000},"page":"381","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Heat Treatment and Fracture Behavior of Aluminum\/Steel FSW Joints: A Comprehensive Analysis of a Curved Interface"],"prefix":"10.3390","volume":"9","author":[{"given":"Tiago Oliveira Gon\u00e7alves","family":"Teixeira","sequence":"first","affiliation":[{"name":"Department of Mechanical Engineering, Faculty of Engineering of the University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"}]},{"given":"Reza","family":"Beygi","sequence":"additional","affiliation":[{"name":"Department of Materials Engineering and Metallurgy, Faculty of Engineering, Arak University, Arak 38156-8-8349, Iran"}]},{"ORCID":"https:\/\/orcid.org\/0009-0005-6181-9938","authenticated-orcid":false,"given":"Masih Bolhasani","family":"Hesari","sequence":"additional","affiliation":[{"name":"Department of Materials Engineering and Metallurgy, Faculty of Engineering, Arak University, Arak 38156-8-8349, Iran"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1933-0865","authenticated-orcid":false,"given":"Ricardo Jo\u00e3o Camilo","family":"Carbas","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering, Faculty of Engineering of the University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"}]},{"given":"Eduardo Andre Sousa","family":"Marques","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering, Faculty of Engineering of the University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9478-9783","authenticated-orcid":false,"given":"Mohammad Mehdi","family":"Kasaei","sequence":"additional","affiliation":[{"name":"Institute of Science and Innovation in Mechanical and Industrial Engineering (INEGI), Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3272-4591","authenticated-orcid":false,"given":"Lucas Filipe Martins","family":"da Silva","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering, Faculty of Engineering of the University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2025,11,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"103316","DOI":"10.1016\/j.ijadhadh.2022.103316","article-title":"Feasibility study on hybrid weld-bonding between dissimilar material for automotive industry","volume":"121","author":"Nonnenmann","year":"2023","journal-title":"Int. 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