Welding and Joining of Metallic Materials: Microstructure and Mechanical Properties, 2nd Edition

A special issue of Crystals (ISSN 2073-4352). This special issue belongs to the section "Hybrid and Composite Crystalline Materials".

Deadline for manuscript submissions: 31 October 2025 | Viewed by 3187

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Guest Editor
CEMMPRE, Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, 3030-788 Coimbra, Portugal
Interests: multidisciplinary modeling of the mechanical behavior of materials; identification of thin-film properties; combination of computational physics; artificial intelligence; multi-scale simulations and materials characterization; recent exploration into tribology
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Guest Editor
1. Institute of Science and Innovation in Mechanical and Industrial Engineering (INEGI), Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
2. Department of Materials Engineering and Metallurgy, Faculty of Engineering, Arak University, Arak 38156-8-8349, Iran
Interests: welding metallurgy; simulation of welding; friction stir welding; welding of dissimilar materials; adhesive bonding; advanced joining processes
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Following the remarkable success of the first edition of the Special Issue “Welding and Joining of Metallic Materials: Microstructure and Mechanical Properties” (https://www.mdpi.com/journal/crystals/special_issues/D36F0198NS), which published 10 articles, we are pleased to announce the second edition of this Special Issue.

Welding and joining in manufacturing metallic materials are vital processes for several industries including aerospace, automotive, and construction that can create complex assemblies and components. The quality and efficacy of welded joints hinges not only upon utilizing the appropriate joining techniques but also upon the microstructure and mechanical properties of the resulting welds. It is of paramount importance to gain a comprehensive understanding of the relationship between the used joining process parameters, the microstructure and mechanical properties for optimizing welding processes, improving joint integrity, and shape the overall performance of welded structures and streamline fabrication practices.

This Special Issue invites researchers from academia, industry, and research institutions to contribute original research articles, reviews, and perspectives within the scope of welding and joining of metallic materials. This Special Issue aims to bring together a diverse collection of contributions to advance the understanding of welding and joining processes, foster innovation, and facilitate the development of optimized welding practices with improved microstructure and mechanical properties.

Prof. Dr. Ali Khalfallah
Dr. Reza Beygi
Guest Editors

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Keywords

  • friction stir welding
  • laser welding
  • electron beam welding
  • hybrid welding
  • adhesive bonding
  • welding-based additive manufacturing (WAAM)
  • gas metal arc welding (GMAW)
  • gas tungsten arc welding (GTAW)
  • shielded metal arc welding (SMAW)
  • welding parameters and optimization
  • microstructure
  • post-weld heat treatment
  • grain structure
  • phase transformations
  • precipitates
  • defects
  • residual stresses
  • mechanical properties
  • non-destructive testing
  • fatigue analysis
  • fracture mechanics
  • weld integrity
  • reliability assessments

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Related Special Issue

Published Papers (4 papers)

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Research

13 pages, 11060 KiB  
Article
Influence of Sheet Thickness and Process Parameters on the Microstructure and Mechanical Properties of Brazed Welding Used for Cold-Formed Steel Beams
by Iosif Hulka, Viorel Ungureanu, Silviu Saraolu, Alin Popescu and Alexandru Pascu
Crystals 2025, 15(4), 354; https://doi.org/10.3390/cryst15040354 - 12 Apr 2025
Viewed by 234
Abstract
Metal inert gas (MIG) brazing was used to join galvanized thin sheets with thicknesses in the range of 0.8 to 2 mm in a lap joint configuration using CuAl8 wire as filler. The process was used to manufacture built-up cold-formed steel beams [...] Read more.
Metal inert gas (MIG) brazing was used to join galvanized thin sheets with thicknesses in the range of 0.8 to 2 mm in a lap joint configuration using CuAl8 wire as filler. The process was used to manufacture built-up cold-formed steel beams composed of corrugated steel webs and flanges made from thin-walled cold-formed steel lipped channel profiles. The effect of heat input and sheet thickness on joint properties, such as macro- and microstructure, wettability, and mechanical characteristics such as microhardness and tensile strength were investigated. The bead geometry was assessed by studying the wettability of the filler material. The microstructure was investigated by digital and scanning electron microscopy, and the composition in the heat-affected zone (HAZ), interface, and bead was determined by energy dispersive spectroscopy. Formation of Fe–Al intermetallics was observed in the bead at the bead–base material interface. Some pores were noticed that formed due to the evaporation of the zinc coating. The bead shape and mechanical properties were found to be the best when 1.2 and 2 mm sheets were brazed using a heat input of 121.4 J/mm. This suggests that not only the heat input but also the thickness of the sheet metal play a crucial role in the production of MIG brazed joints. Full article
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13 pages, 7809 KiB  
Article
Effects of Nanostructured Functional Ceramics Additives Coatings Electrode on the Structure and Mechanical Properties of SMAW Welded Joints
by Saidov R. Mannapovitch, Rakhimov R. Khamidovich, Kamel Touileb and Joffin Ponnore
Crystals 2025, 15(3), 260; https://doi.org/10.3390/cryst15030260 - 11 Mar 2025
Viewed by 419
Abstract
The present work is a comparative analysis of the properties of welded joints obtained during welding with the developed welding electrodes containing additives of photocatalysts of nanostructured functional ceramics (PNFC) brand ZB-1 (IMAN-7) and the ESAB E6013 welding electrodes. This study investigates the [...] Read more.
The present work is a comparative analysis of the properties of welded joints obtained during welding with the developed welding electrodes containing additives of photocatalysts of nanostructured functional ceramics (PNFC) brand ZB-1 (IMAN-7) and the ESAB E6013 welding electrodes. This study investigates the weld morphology, microstructure, and mechanical properties of Shield metal arc welding (SMAW) welded joints. The results of the studies showed that the introduction of PNFC brand ZB-1 into the coating of welding electrodes up to 1% has a beneficial effect on the melting ability and stability of the welding arc, formation of the bead, microstructure of the weld bead, and mechanical properties of the welded joints. It was found that IMAN-7 electrodes, compared to the ESAB E6013 electrodes, have better performance in terms of arc penetration, bead metal structure, and relative elongation of welded joints. In addition, the high melting capacity of the IMAN-7 electrode allows for economic advantages, such as increased productivity and a two-fold reduction in electrode consumption. Full article
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17 pages, 22813 KiB  
Article
Effect of Oxide’s Thermophysical Properties on 2205 Duplex Stainless Steels ATIG Welds
by Rachid Djoudjou, Kamel Touileb, Elawady Attia, Abousoufiane Ouis, Abdeljlil Chihaoui Hedhibi, Hany S. Abdo and Ibrahim AlBaijan
Crystals 2024, 14(11), 973; https://doi.org/10.3390/cryst14110973 - 10 Nov 2024
Viewed by 1262
Abstract
Duplex stainless-steel grade 2205 (2205 DSS) is the most widely used of the current duplex materials. The duplex steel alloy is characterized by high strength and high corrosion resistance through enhancing nitrogen and molybdenum contents. The activated tungsten inert gas (ATIG) welding technique [...] Read more.
Duplex stainless-steel grade 2205 (2205 DSS) is the most widely used of the current duplex materials. The duplex steel alloy is characterized by high strength and high corrosion resistance through enhancing nitrogen and molybdenum contents. The activated tungsten inert gas (ATIG) welding technique uses the same equipment as tungsten inert gas (TIG), but prior to the welding operation, a thin layer of flux is deposited. Activation fluxes are known to influence the shape and energy characteristics of the arc. They promote the change in shapes and dimensions of the welds, namely, increasing the depth and narrowing the weld width. This work is dedicated to investigate the influence of the thermophysical properties of individual metal oxide fluxes on 2205 DSS welding morphology. It helps also to identify the recommended flux properties in order to perform full penetrated ATIG welds. Thirteen kinds of oxides (SiO2, TiO2, Fe2O3, Cr2O3, ZnO, Mn2O3, V2O5, MoO3, Co3O4, SrO, ZrO2, CaO, and MgO) have been tested and three current intensity levels (120, 150 and 180 A) have been considered. The results showed that the main input factors affecting the weld depth (D) were the welding current intensity with a contribution of up to 53.36%, followed by the oxides enthalpy energy with 15.05% and then by the difference between the oxides and the base metal of 2205 DSS (BM 2205 DSS) melting points with a contribution of 9.71% of the data variance. The conditions on individual oxides’ thermophysical properties to achieve full penetrated weld beads have been also revealed. Full article
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15 pages, 5597 KiB  
Article
Effects of Oxide Powders as Activating Flux on AMIG 304L Welds
by Kamel Touileb, Rachid Djoudjou, Abousoufiane Ouis, Abdeljlil Chihaoui Hedhibi, Hussein Alrobei, Ibrahim Abdullah Alnaser, Rizwan Ahmed Malik and Ubair Abdus Samad
Crystals 2024, 14(10), 902; https://doi.org/10.3390/cryst14100902 - 18 Oct 2024
Viewed by 863
Abstract
Activating metal inert gas (AMIG) welding was designed to address difficulties with MIG welding, such as the limitation on workpiece thickness that may be welded in a single pass. This investigation was carried out on 304L stainless steel using ER 308L as a [...] Read more.
Activating metal inert gas (AMIG) welding was designed to address difficulties with MIG welding, such as the limitation on workpiece thickness that may be welded in a single pass. This investigation was carried out on 304L stainless steel using ER 308L as a filler metal. Five oxides (SiO2, TiO2, Fe2O3, Mn2O3, and Cr2O3) have been investigated without edge preparation. The welded joints were evaluated for weld morphology, microstructure, mechanical properties, and corrosion, and the findings were compared. The depth of the AMIG weld was determined to be greater than that of the MIG weld. The microstructure is composed of austenitic and retained delta ferrite with 3.3% for MIG and up to 8% for AMIG weld carried out with Cr2O3 oxide flux, the tensile strength is up to 604 MPa when using Cr2O3 oxide against MIG weld (532 MPa), and the resistance to sudden load in AMIG welds (189 J/cm2) is higher than that of MIG weld (149 J/cm2). The corrosion resistance of the weld made with Fe2O3 oxide flux is greater than that of the other AMIG and MIG welds, as well as the parent metal. The AMIG welding technique variant enhances productivity and decreases the cost and energy consumption of the welding material compared to the traditional MIG process. This allows for joining the same thickness without affecting mechanical properties and corrosion resistance, meeting the industry’s requirements. Full article
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