Microstructure and Mechanical Properties of Metals Welding Joints

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

Deadline for manuscript submissions: closed (30 June 2023) | Viewed by 3813

Special Issue Editors

Department of Welding Engineering, Institution of Engineering and Technology, South Ural State University, Chelyabinsk, Russia
Interests: resistance welding; gas metal arc welding; quality control; online monitoring; microstructure

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Guest Editor
Department of Mechanical Engineering, University of Coimbra, 3030-788 Coimbra, Portugal
Interests: structural integrity; fatigue; fracture mechanics; finite element method; fiber-reinforced composites; environmental effects; additive manufacturing
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Guest Editor
Department of Production and Industrial Engineering, Birla Institute of Technology, Mesra, Ranchi, India
Interests: laser-based manufacturing; welding and joining; modeling and simulation

Special Issue Information

Dear Colleagues,

Welding is one of the most commonly used joining techniques for various materials nowadays. Welding technology has undergone many improvements and innovations, such as in the examples of high-energy density processes or solid state welding processes and mixed metal diffusion and bonding using a couple of basic welding techniques. Compared to other joining techniques, such as bulky riveted/butt joints, the welding process requires less production time and also offers advantages such as not producing holes, which weaken the structure, in addition to lower production costs. However, the welding process itself, including the heat source, determines the thermal history of the component, resulting in changes in metallic material, residual stresses, and geometric discontinuities that adversely affect the structural integrity and fatigue performance of the welded joint.

For a typical kind of metal material, the welding process, microstructure, and performance analysis of welded joints are conducted. At the same time, attention is paid to matching the geometric characteristics of the welded joint, the inhomogeneity of microstructure and mechanical properties, and the influence of welding process parameters on the microstructure and properties.

This Special Issue aims to collect original works dealing with new advances in the microstructural and mechanical characterization of welded joints through numerical simulations or experiments.

Dr. Dawei Zhao
Prof. Dr. Ricardo Branco
Dr. Fábio Fernandes
Dr. Bappa Acherjee
Guest Editors

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Keywords

  • microstructure
  • fatigue
  • failure mode
  • failure mechanism
  • assisted-welding techniques
  • microstructure transformation
  • welding design
  • residual stress
  • welding stimulation
  • welding quality control

Published Papers (3 papers)

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Research

12 pages, 2808 KiB  
Article
Evaluation of Laser Lap Weldability between the Titanium Alloy Ti-6Al-4V and Aluminum Alloy 6060-T6
by Fábio A. O. Fernandes, José J. M. Gonçalves and António B. Pereira
Crystals 2023, 13(10), 1448; https://doi.org/10.3390/cryst13101448 - 29 Sep 2023
Cited by 1 | Viewed by 723
Abstract
This work investigates laser weldability between non-ferrous dissimilar metallic materials, specifically the aluminum 6060-T6 alloy and titanium Ti-6Al-4V. These materials are used in several engineering applications, including aerospace. In a simple lap joint configuration, these were welded with a pulsed Nd:YAG laser, with [...] Read more.
This work investigates laser weldability between non-ferrous dissimilar metallic materials, specifically the aluminum 6060-T6 alloy and titanium Ti-6Al-4V. These materials are used in several engineering applications, including aerospace. In a simple lap joint configuration, these were welded with a pulsed Nd:YAG laser, with direct incidence on the titanium piece. Preheating and post-weld heating were introduced to mitigate cracking issues. Based on the primary experiments, the main variables were the peak laser power, which varied between 60 and 70%, and the number of beads (a single bead and double beads). The quality of the welds was assessed via uniaxial tensile tests, subjecting the joint to shear loading. Additionally, SEM micrographs were obtained to analyze the quality of the fusion between the dissimilar alloys. The higher strength of the welded samples achieved was 90 MPa, which is close to the reported value for the aluminum base material. A fracture occurred near the weld bead in the heat-affected zone (HAZ). The observed microporosities and cracks explain the lower value as compared to the base material. Although these were mitigated through the thermal cycle strategy employed and the shielding gas, they were not entirely avoided. Full article
(This article belongs to the Special Issue Microstructure and Mechanical Properties of Metals Welding Joints)
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12 pages, 6633 KiB  
Article
Microstructure and Mechanical Property Evolution of Robotic Friction Stir-Welded Al–Li Alloys
by Yisong Wang, Haitao Jiang, Xiaoyan Wu and Qiang Meng
Crystals 2023, 13(4), 582; https://doi.org/10.3390/cryst13040582 - 29 Mar 2023
Cited by 1 | Viewed by 1050
Abstract
2198 aluminum–lithium alloy was friction stir-welded with a KUKA Robot integrated with a compact friction stir-welding head with a rotation speed of 800 rpm at different welding speeds. The real-time tool force in the three directions of Fx, Fy and Fz was measured [...] Read more.
2198 aluminum–lithium alloy was friction stir-welded with a KUKA Robot integrated with a compact friction stir-welding head with a rotation speed of 800 rpm at different welding speeds. The real-time tool force in the three directions of Fx, Fy and Fz was measured with a load sensor. Mechanical properties and microstructure evolution were investigated systematically. The results showed that Fz force increased from 3.2 kN to 8.5 kN as welding speed increased from 50 mm/min to 500 mm/min. Ultimate tensile strength of 383 MPa, 88% of base metal, was obtained when the welding speed was 100 mm/min. The nugget zone consisted of refined grains with an average size of 4 μm. TEM investigation demonstrates that T1 precipitation predominated in the base metal and disappeared in the nugget zone, as a small amount of δ’ was retained. The W-shape hardness profile in all weldments and higher welding speed lead to a higher hardness value. Full article
(This article belongs to the Special Issue Microstructure and Mechanical Properties of Metals Welding Joints)
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11 pages, 9073 KiB  
Article
Interfacial Microstructure and Mechanical Properties of Titanium/Sapphire Joints Brazed with AuSn20 Filler Metal
by Yi Zhou, Hong Bian, Xiaoguo Song, Yuzhen Lei, Mingjun Sun, Weimin Long, Sujuan Zhong and Lianhui Jia
Crystals 2022, 12(12), 1687; https://doi.org/10.3390/cryst12121687 - 22 Nov 2022
Cited by 4 | Viewed by 1290
Abstract
In this study, C-plane (0001) sapphire was successfully brazed to titanium using AuSn20 filler metal, following metallization on the surface of the sapphire with Sn-3Ti (wt.%). At 1000 °C, Sn-3Ti had good wettability on the surface of the sapphire, with the lowest equilibrium [...] Read more.
In this study, C-plane (0001) sapphire was successfully brazed to titanium using AuSn20 filler metal, following metallization on the surface of the sapphire with Sn-3Ti (wt.%). At 1000 °C, Sn-3Ti had good wettability on the surface of the sapphire, with the lowest equilibrium contact angle of 57°. The reaction phases in the joints were identified, and the typical interfacial microstructure of the brazed joint brazed at 550 °C for 30 min was titanium substrate/Au-Sn-Ti layer/Ti6Sn5 + AuSn2 + AuSn4 + massive Au-Sn-Ti/TiO phase/sapphire. The shear test was utilized to evaluate the bonding strength of the titanium/sapphire joints. The highest shear strength reached 18.7 MPa when brazed at 550 °C for 35 min. The crack was initiated at the sapphire/brazing seam interface and propagated into the Au-Sn-Ti reaction layer. Full article
(This article belongs to the Special Issue Microstructure and Mechanical Properties of Metals Welding Joints)
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