Physical Mechanism of Welding of Metallic Materials

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

Deadline for manuscript submissions: closed (31 December 2023) | Viewed by 18441

Special Issue Editors


E-Mail Website
Guest Editor
Department of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, China
Interests: welding physics; plasma arc welding; wire arc additive manufacturing; modelling and simulation

E-Mail Website
Guest Editor
Department of Materials Processing, Beijing Universtity of Aeronautics and Astronautics, Beijing 100191, China
Interests: arc welding; pulsed welding; plasma; visualisation

Special Issue Information

Dear Colleagues,

From micro-nano devices such as chips to large structures such as aircraft carriers, the application of advanced welding technologies is indispensable. Welding is a process of interaction between a specific heat source and a specific material system, involving a series of complex thermal and mechanical phenomena, such as heat and mass transfer, fluid flow, electromagnetic action, melting, solidification, microstructure evolution, plastic deformation and so on. The deep understanding of the welding physical mechanism is helpful to optimize welding process, control welding quality and improve welding efficiency. Through the modelling and simulation of welding processes, the product development cycle is significantly shortened, the production cost is reduced, the welding quality is greatly improved, and the safety and reliability of the welding structure is guaranteed. The application of new materials and new technologies also continuously put forward new requirements for the new welding approaches, mechanisms and technologies. Research is actively being carried out across the world to clarify the mechanisms of welding processes scientifically, and to develop more advanced welding processes. However, challenges still exist, and further work is always needed.

This special issue aims to collect the recent discovery in welding physical mechanism, both from experimental characterization and numerical modelling. Topics covered in this Special Issue include but are not limited to: new discovery in traditional welding process, physical mechanism of novel welding process, novel welding materials and structures design, state-of-the-art scientific developments in welding metallurgy, material weldability, and the evaluation of welding joints.

This special issue endeavours to share recent advances and provide future insights in this crucial area, help researchers to better follow the newest research progress.

Prof. Dr. Fan Jiang
Dr. Mingxuan Yang
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Crystals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Published Papers (12 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

Jump to: Review

11 pages, 5914 KiB  
Article
Combined Effect of In and Ce on Microstructure and Properties of Ag10CuZnSn Low-Silver Brazing Filler Metals
by Jiachen Xu, Yucan Fu, Yan Yang, Zhen Li, Li Wang, Songbai Xue and Jie Wu
Crystals 2023, 13(8), 1285; https://doi.org/10.3390/cryst13081285 - 20 Aug 2023
Viewed by 748
Abstract
In this study, trace amounts of In and Ce elements were composite added into a Ag10CuZnSn low-silver brazing filler metal, and the effects of the composite alloying on the solidus and liquidus temperatures, the spreading performance, the microstructure of the filler metal, and [...] Read more.
In this study, trace amounts of In and Ce elements were composite added into a Ag10CuZnSn low-silver brazing filler metal, and the effects of the composite alloying on the solidus and liquidus temperatures, the spreading performance, the microstructure of the filler metal, and the mechanical properties of the joints prepared with these filler metals were studied. The results reveal that the In element can significantly decrease the solidus and the liquidus temperatures of the Ag10CuZnSn alloy, while the Ce element has little effect on the melting temperature. Trace amounts of In and Ce elements can obviously increase the spreading areas of the filler metals on the pure Cu and 304 stainless steel base metals. The In and Ce elements can refine the microstructure of the filler metals. When the contents of In and Ce are 1.5 wt% and 0.15 wt%, respectively, the microstructure refinement effect is the most obvious, and the shear strength of the 304 stainless steel brazed joint also achieves a maximum value of 375 MPa. Excessive addition of In and Ce can form brittle intermetallic compounds in the filler metal, decreasing the brazed joints' shear strength. Full article
(This article belongs to the Special Issue Physical Mechanism of Welding of Metallic Materials)
Show Figures

Figure 1

28 pages, 14183 KiB  
Article
Exploring the Impact of Cooling Rate on Microstructural Features, Mechanical Properties, and Corrosion Resistance of a Novel Nb-Stabilized Super Duplex Stainless Steel in Shielded Metal Arc Welding
by Ángelo Oñate, Enrique Torres, Diego Olave, Jesús Ramírez, Carlos Medina, Juan Pablo Sanhueza, Manuel Melendrez, Víctor Tuninetti and David Rojas
Crystals 2023, 13(8), 1192; https://doi.org/10.3390/cryst13081192 - 31 Jul 2023
Cited by 2 | Viewed by 1022
Abstract
The corrosion and mechanical response produced by quenching in the welded joint of a new Nb-doped stainless steel designed by the CALPHAD method and produced by open-atmosphere casting with recycled materials were investigated to contribute to the circular economy and to establish disruptive [...] Read more.
The corrosion and mechanical response produced by quenching in the welded joint of a new Nb-doped stainless steel designed by the CALPHAD method and produced by open-atmosphere casting with recycled materials were investigated to contribute to the circular economy and to establish disruptive manufacturing criteria based on metallurgical principles. The steel was initially subjected to solubilization heat treatment and partial solubilization treatment at 1090 °C to obtain an appropriate α/γ balance and carbide solubilization. It was then welded by the SMAW process, quenched, and tempered at three different cooling rates. As a result, a good fit between the phases predicted by the CALPHAD method and those observed by X-ray diffraction and scanning electron microscopy were obtained, with minor differences attributable to the precipitation and diffusion kinetics required for dissolution or nucleation and growth of the phases in the system. The forced air quenching mechanism was identified as providing an α/γ phase equilibrium equivalent to 62/38 as the most effective quenching method for achieving the optimum mechanical and corrosion response, even with the post-weld σ phase and showing superior results to those of the base metal. The outstanding mechanical and corrosion responses resulted from a proper balance of the primary phases in the duplex steel with a precipitation-strengthening mechanism. The damage tolerance obtained by forced air quenching was superior to that obtained by water and air quenching, with a PSE of 24.71 GPa% post-welding. Full article
(This article belongs to the Special Issue Physical Mechanism of Welding of Metallic Materials)
Show Figures

Figure 1

19 pages, 4703 KiB  
Article
Study on the Depth and Evolution of Keyholes in Plasma-MIG Hybrid Welding
by Xinglin Miao, Hongtao Zhang, Wenhuan Cao, Zhenyu He, Bo Wang, Fuchen Ge and Jianguo Gao
Crystals 2023, 13(3), 412; https://doi.org/10.3390/cryst13030412 - 27 Feb 2023
Cited by 1 | Viewed by 1050
Abstract
Keyholes are very important to the Plasma-MIG hybrid welding process, weld formation, and quality. With the purpose of studying the effect of the main welding parameters (plasma current, MIG current, magnetic field intensity, and welding velocity) on keyhole depth and the interaction among [...] Read more.
Keyholes are very important to the Plasma-MIG hybrid welding process, weld formation, and quality. With the purpose of studying the effect of the main welding parameters (plasma current, MIG current, magnetic field intensity, and welding velocity) on keyhole depth and the interaction among parameter factors, the experiment was designed by the response surface method. In addition, the prediction model with keyhole depth as the response value was obtained. The model shows the important degree of influence of each factor on keyhole depth. It shows that there is an obvious interaction between plasma current and MIG current, while there is no obvious correlation between other parameters. The temperature field of the Plasma-MIG welding process under certain parameters was obtained by using Fluent software for numerical simulation, and the evolution behavior of the keyhole was analyzed. Based on the simulation results, the metal flow mode and the movement mechanism of the keyhole are described. Full article
(This article belongs to the Special Issue Physical Mechanism of Welding of Metallic Materials)
Show Figures

Figure 1

14 pages, 5738 KiB  
Article
Overlapping Features and Microstructures of Coarse Grain Heat-Affected Zones in Swing Arc Narrow Gap GMA Welded EH40 Grade Steels
by Zhida Ni, Fengya Hu, Bolun Dong, Xiaoyu Cai and Sanbao Lin
Crystals 2023, 13(1), 33; https://doi.org/10.3390/cryst13010033 - 25 Dec 2022
Cited by 1 | Viewed by 1077
Abstract
Swing arc narrow gap GMA welding experiments were carried out with a Box–Behnken response surface design. Weld metal and heat-affected sizes were measured from the joints obtained, and an ANOVA was performed to obtain well-fitting models for definition of the heat-affected length. Overlapping [...] Read more.
Swing arc narrow gap GMA welding experiments were carried out with a Box–Behnken response surface design. Weld metal and heat-affected sizes were measured from the joints obtained, and an ANOVA was performed to obtain well-fitting models for definition of the heat-affected length. Overlapping patterns and microstructures were analyzed and observed in zones within the heat-affected length through the thickness direction. In addition, thermal processes in typical zones of HAZs were calculated by FEM and analyzed to explain the patterns in the typical coarse grain heat-affected zones (CG-HAZs) with thermal simulated microstructures attached. It was realized that a single pass could only be confused with an austenitized process by two passes. The coarse grain heat-affected zone of a single pass could be divided into an unaltered coarse grain heat-affected zone (UACG-HAZ), a supercritically reheated coarse grain heat-affected zone (SCRCG-HAZ) and an intercritically reheated heat-affected zone (IRCG-HAZ). It is likely that there would be an intercritically reheated UACG-HAZ upon the UACG-HAZ. The microstructures in the CG-HAZs and the UACG-HAZ were mainly lath bainite and a little acicular ferrite; the microstructures in the SCRCG-HAZ were short lath bainite, granular bainite and acicular ferrite and the microstructures in the IRCG-HAZ were massive textures and secondary austenite decomposition products. The cooling times in the typical bainite transformation procedures were similar to one another in a secondary austenitized process and significantly longer than those in a single austenitized thermal cycle, which caused similar patterns in reheated CG-HAZs and an increase in acicular ferrite compared to CG-HAZs. The prior austenite grain sizes caused differences among the reheated CG-HAZs. Full article
(This article belongs to the Special Issue Physical Mechanism of Welding of Metallic Materials)
Show Figures

Figure 1

11 pages, 2945 KiB  
Article
Electron-Beam Welding Cu and Al6082T6 Aluminum Alloys with Circular Beam Oscillations
by Darina Kaisheva, Angel Anchev, Vladimir Dunchev, Georgi Kotlarski, Borislav Stoyanov, Maria Ormanova and Stefan Valkov
Crystals 2022, 12(12), 1757; https://doi.org/10.3390/cryst12121757 - 04 Dec 2022
Cited by 5 | Viewed by 1829
Abstract
In this study, we present the results from electron-beam welding operations applied on copper and Al6082T6 aluminum alloys. The influence of beam-scanning geometries on the structure and mechanical properties of the welded joint is studied. The experiments were conducted using a circle oscillation [...] Read more.
In this study, we present the results from electron-beam welding operations applied on copper and Al6082T6 aluminum alloys. The influence of beam-scanning geometries on the structure and mechanical properties of the welded joint is studied. The experiments were conducted using a circle oscillation mode with an oscillation radius of 0.1 mm and 0.2 mm. The beam deflection was set to 0.4 mm with respect to the side of the aluminum alloy, and the beam power was set at 2700 W. The phase composition of the obtained welded joints was studied by X-ray diffraction (XRD). Scanning electron microscopy (SEM) was used for the investigation of the microstructure of the joints. The chemical composition was investigated by using energy-dispersive X-ray spectroscopy (EDX). The mechanical properties were studied by micro-hardness investigations. The fusion zone of the weld seam contains three phases—an aluminum matrix, an ordered solid solution of copper and aluminum in the form of CuAl2, and pure copper. Electron beam-scanning geometries have significant influences on the structure of the weld. Increasing the beam oscillation’s radius leads to a decrease in intermetallic phases and improves homogeneity. The measured microhardness values in the fusion zone are much higher than the ones measured in the base metals due to the formation of intermetallic phases. The microhardness of the weld joint formed using an oscillation radius of 0.2 mm was much lower compared to the one formed using an oscillation radius of 0.1 mm. Full article
(This article belongs to the Special Issue Physical Mechanism of Welding of Metallic Materials)
Show Figures

Figure 1

11 pages, 3876 KiB  
Article
Reliability of SnPbSb/Cu Solder Joint in the High-Temperature Application
by Jiachen Xu, Yucan Fu, Xiaoxiao Zhou, Junqian Zhang and Songbai Xue
Crystals 2022, 12(12), 1724; https://doi.org/10.3390/cryst12121724 - 28 Nov 2022
Viewed by 1315
Abstract
With the continuous miniaturization and increase in functionality of the electronic devices used in the aerospace and national defense industries, the requirements for reliability of the solder joints in these devices keep increasing. In this study, a SnPbSb solder with excellent wettability was [...] Read more.
With the continuous miniaturization and increase in functionality of the electronic devices used in the aerospace and national defense industries, the requirements for reliability of the solder joints in these devices keep increasing. In this study, a SnPbSb solder with excellent wettability was used as the research object, and the effects of high-temperature aging at 150 °C on the microstructure and mechanical properties of SnPbSb/Cu solder joints were investigated according to the relevant industry standards. It was found that high-temperature aging does not change the eutectic structure of the SnPbSb solder, but it does significantly coarsen the Sn-rich phase and the Pb-rich phase in the solder. In addition, the interfacial intermetallic compound (IMC) layer in the SnPbSb/Cu solder joint changes from a Cu6Sn5 single layer to a Cu6Sn5/Cu3Sn double layer after the aging, and the thickness of the IMC layer increases greatly. High-temperature aging significantly deteriorates the mechanical properties of the solder joints. After aging at 150 °C for 1000 h, the shear strength of the SnPbSb/Cu solder joints decreased by 45.39%, while the ductile fracture mode did not change. Full article
(This article belongs to the Special Issue Physical Mechanism of Welding of Metallic Materials)
Show Figures

Figure 1

9 pages, 3231 KiB  
Article
Microstructure and Mechanical Properties of the Ternary Gas Shielded Narrow-Gap GMA Welded Joint of High-Strength Steel
by Zhida Ni, Fengya Hu, Yunhe Li, Sanbao Lin and Xiaoyu Cai
Crystals 2022, 12(11), 1566; https://doi.org/10.3390/cryst12111566 - 03 Nov 2022
Cited by 2 | Viewed by 1159
Abstract
An 80%Ar-10%CO2-10%He ternary gas mixture was used as the shielding gas during the narrow-gap welding of thick Q690E high-strength steel plates. Complete and defect-free welded joints were obtained, and the microstructure and mechanical properties of the welded joint were investigated. The [...] Read more.
An 80%Ar-10%CO2-10%He ternary gas mixture was used as the shielding gas during the narrow-gap welding of thick Q690E high-strength steel plates. Complete and defect-free welded joints were obtained, and the microstructure and mechanical properties of the welded joint were investigated. The weld zone consists of a solidification area and interlayer zone, and the heat-affected zone consists of a coarse-grain heat-affected zone (CG-HAZ) and a fine-grain heat-affected zone (FG-HAZ). The microstructures of the weld zone are mainly lath bainite (LB), acicular ferrite (AF), and granular bainite (GB). The microstructure of the CG-HAZ is lath martensite (LM) and the microstructure of FG-HAZ is GB. Methods with different heat inputs were used to study their effects on the mechanical properties of the welded joint. It was found that the microstructure and mechanical properties of the welded joints are better with lower heat input. With tandem wire narrow-gap GMA welding, the tensile strength of the joints declined from 795.3 to 718.3 MPa and the impact toughness at −40 °C resulted in a weak position in the weld zone, which declined from 76~81 J to 55~69 J, when the welding speed reduced from 350 to 250 mm/min. With oscillating-arc narrow-gap GMA welding, the tensile strength achieved 853.4 MPa and the impact toughness at −40 °C was around 69~87 J. The results indicated that, under the appropriate heat input, the tensile strength of the joint exceeds 770 MPa and the low temperature impact toughness at −40 °C exceeds 69 J. A 155 mm-thick Q690E steel welded joint was obtained and the mechanical properties of the welded joint meets the requirements of the offshore drilling platforms. Full article
(This article belongs to the Special Issue Physical Mechanism of Welding of Metallic Materials)
Show Figures

Figure 1

21 pages, 7049 KiB  
Article
Modeling Hardness Evolution during the Post-Welding Heat Treatment of a Friction Stir Welded 2050-T34 Alloy
by Sébastien Galisson, Denis Carron, Philippe Le Masson, Georgios Stamoulis, Eric Feulvarch and Gilles Surdon
Crystals 2022, 12(11), 1543; https://doi.org/10.3390/cryst12111543 - 28 Oct 2022
Cited by 1 | Viewed by 1073
Abstract
A unified constitutive model of yield strength evolution during heat treatment has been revised to simulate the hardness evolution during the post-welding heat treatment of AA2050-T34 Friction Stir Welded (FSW) plates. The model considers the strengthening by dislocations, solid solution, clusters, and the [...] Read more.
A unified constitutive model of yield strength evolution during heat treatment has been revised to simulate the hardness evolution during the post-welding heat treatment of AA2050-T34 Friction Stir Welded (FSW) plates. The model considers the strengthening by dislocations, solid solution, clusters, and the T1 phase. As a result, the successful prediction of yield strength evolution during the aging of AA2050 with different initial tempers has been achieved. The kinetics of precipitation of the T1 phase during heat treatment has been characterized by electrical resistivity on the unwelded and FSW samples. The obtained results have been used to check the ability of the model to simulate the evolution of the relative volume fraction of the T1 phase and hardness during the post-welding heat treatment in the different zones of FSW samples. Despite some observed discrepancies on the top and bottom of the weld joint, the revised numerical model captures well the overall hardness profile after the post-weld heat treatment. Full article
(This article belongs to the Special Issue Physical Mechanism of Welding of Metallic Materials)
Show Figures

Figure 1

11 pages, 3822 KiB  
Article
Effect of Arc Behaviour and Metal Transfer Process on Aluminium Welds during Ultrasonic Frequency Pulsed GMAW
by Hao Zheng, Bojin Qi, Mingxuan Yang and Heng Liu
Crystals 2022, 12(5), 586; https://doi.org/10.3390/cryst12050586 - 22 Apr 2022
Cited by 2 | Viewed by 1393
Abstract
In order to study the influence of a novel current waveform control method of ultrasonic-frequency pulse (UFP) on arc behaviour, metal transfer process and the welds formation, monitoring system and image processing algorithms were employed for extracting the welding characters. Mechanics, defect, microstructure [...] Read more.
In order to study the influence of a novel current waveform control method of ultrasonic-frequency pulse (UFP) on arc behaviour, metal transfer process and the welds formation, monitoring system and image processing algorithms were employed for extracting the welding characters. Mechanics, defect, microstructure and mechanical property analysis based on pulsed GMAW was carried out. The results showed that, compared with the conventional pulsed GMAW, the ultrasonic-frequency pulse not only increased axial arc plasma jet force, arc force and droplet falling acceleration, but also suppressed the welded porosity formation, decelerated the microstructure regional element segregations, refined the grain and increased the microhardness property of welded joint. The study helped to reveal the mechanism for improving welding quality of ultrasonic-frequency pulsed GMAW. Full article
(This article belongs to the Special Issue Physical Mechanism of Welding of Metallic Materials)
Show Figures

Figure 1

10 pages, 4044 KiB  
Article
Effect of Arc Length on Oxygen Content and Mechanical Properties of Weld Metal during Pulsed GMAW
by Jiachen Xu, Xiaoxiao Zhou and Dawei Zhu
Crystals 2022, 12(2), 176; https://doi.org/10.3390/cryst12020176 - 26 Jan 2022
Cited by 2 | Viewed by 1965
Abstract
Pulsed gas metal arc weld (GMAW) was widely used for the advantages of controllable heat input, all-position welding, and no spatter. In order to obtain an ideal welding process, the stability of the arc length was studied in many researches, but the influence [...] Read more.
Pulsed gas metal arc weld (GMAW) was widely used for the advantages of controllable heat input, all-position welding, and no spatter. In order to obtain an ideal welding process, the stability of the arc length was studied in many researches, but the influence of arc length on the properties of weld metal was ignored. In this paper, the effect of arc length on oxygen content and mechanical properties of weld metal during pulsed GMAW was studied. Q690 high strength steel was selected as the base metal, and ER69-G solid wire, with a diameter of 1.2 mm, was used as the electrode wire. Additionally, the shielding gas and the wire feed rate were 82% Ar + 18% CO2 and 4 m/min, respectively. The results showed that as the arc length raised from 2.9 mm to 9.2 mm, the oxidation reacted more completely in the droplet transfer zone, and the oxygen content of the weld metal increased significantly. The tensile strength of the weld metal reduced but the −40 °C impact energy heightened. Due to the longer arc, the proportion of acicular ferrite (AF) in the microstructure decreased, but the proportion of lath bainite (LB) and granular bainite (GB) decreased. The higher oxygen content of weld metal was useful for the formation of inclusions, which promoted the nucleation of acicular ferrite and dimples, contributing to the growth of plasticity and toughness of weld metal. Full article
(This article belongs to the Special Issue Physical Mechanism of Welding of Metallic Materials)
Show Figures

Figure 1

11 pages, 7722 KiB  
Article
Development of a Novel Low-Silver Cu-P Brazing Filler Metal Bearing Sn
by Jie Wu, Songbai Xue and Qingcheng Luo
Crystals 2022, 12(1), 66; https://doi.org/10.3390/cryst12010066 - 04 Jan 2022
Cited by 3 | Viewed by 1455
Abstract
The flame brazing of H62 brass using a novel, low-silver Cu-P brazing filler metal was investigated in this study. The effect of the addition of a trace amount of Sn on the microstructure and properties of Cu-7P-1Ag filler metals was analyzed by means [...] Read more.
The flame brazing of H62 brass using a novel, low-silver Cu-P brazing filler metal was investigated in this study. The effect of the addition of a trace amount of Sn on the microstructure and properties of Cu-7P-1Ag filler metals was analyzed by means of X-ray diffractometer, scanning electron microscopy and energy dispersive spectrometer. The addition of trace Sn led to a decrease in the solidus and liquidus temperatures of Cu-7P-1Ag filler metals. Meanwhile, the spreading performance of the filler metals on a H62 brass substrate was improved. The microstructure of the low-silver, Cu-P brazing filler metal was mainly composed of α-Ag solid solution, α-Cu solid solution and Cu3P; an increase of Sn content led to the transformation of the microstructure of the joints from a block to a lamellar structure. When the Sn content was 0.5 wt. %, the shear strength of the joint at room temperature reached 348 MPa, and the fracture morphologies changed from a cleavage to a quasi-cleavage structure. Full article
(This article belongs to the Special Issue Physical Mechanism of Welding of Metallic Materials)
Show Figures

Figure 1

Review

Jump to: Research

23 pages, 22661 KiB  
Review
Review of Additive Manufacturing Techniques for Large-Scale Metal Functionally Graded Materials
by Ruiying Zhang, Fan Jiang, Long Xue and Junyu Yu
Crystals 2022, 12(6), 858; https://doi.org/10.3390/cryst12060858 - 17 Jun 2022
Cited by 6 | Viewed by 3378
Abstract
Functionally graded materials (FGMs), which constitute a new type of composite material, have received considerable attention in industry because of the spatial gradient of their composition and the microstructure-induced gradient in their material performance, which make them better suited for high-performance multifunctional applications. [...] Read more.
Functionally graded materials (FGMs), which constitute a new type of composite material, have received considerable attention in industry because of the spatial gradient of their composition and the microstructure-induced gradient in their material performance, which make them better suited for high-performance multifunctional applications. Additive manufacturing (AM) has become one of the most promising techniques for the manufacture of materials and structures because of its high flexibility. The combination of advanced materials (FGMs) and advanced manufacturing methods (AM) is expected to facilitate the further development of such engineering materials. In this paper, the definition, historical development and material gradient types of FGMs are introduced. The classification, process principle and typical research results of the AM of metal FGMs are summarized and discussed. In particular, the research status of wire and arc additive manufacture (WAAM), which is more suitable for the preparation of large-scale metal FGMs, is reviewed in detail according to the types of FGMs, and a double-wire bypass plasma arc additive manufacturing technique, which is suitable for inducing a gradient along the direction of single-pass cladding, is proposed. On the basis of this summary of the important achievements made to date, future research is proposed. Full article
(This article belongs to the Special Issue Physical Mechanism of Welding of Metallic Materials)
Show Figures

Figure 1

Back to TopTop