Effect of post weld heat treatment on weldability of high entropy alloy welds

Nam, Hyunbin; Park, Chulho; Kim, Cheol-Hee; Kim, Hyoungseop; Kang, Ning

doi:10.1080/13621718.2017.1405564

Cited by 67 publications

(26 citation statements)

References 30 publications

(33 reference statements)

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“…The trend of the other reported works on LBW showed a difference in terms of the hardness changes in the FZ [ 19 , 27 ]. In the work by Sokkalingam et al [ 19 ], 1 mm thick sheets of Al0.5CoCrFeNi were welded with a power of 1.5 kW and a traverse speed of 600 mm/min.…”

Section: Welding Of Heas In Different Welding Processesmentioning

confidence: 69%

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Welding of High Entropy Alloys—A Review

Guo

Tang

Rothwell

et al. 2019

Entropy

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High-entropy alloy (HEA) offers great flexibility in materials design with 3–5 principal elements and a range of unique advantages such as good microstructure stability, mechanical strength over a broad range of temperatures and corrosion resistance, etc. Welding of high entropy alloy, as a key joining method, is an important emerging area with significant potential impact to future application-oriented research and technological developments in HEAs. The selection of feasible welding processes with optimized parameters is essential to enhance the applications of HEAs. However, the structure of the welded joints varies with material systems, welding methods and parameters. A systemic understanding of the structures and properties of the weldment is directly relevant to the application of HEAs as well as managing the effect of welding on situations such as corrosion that are known to be a service life limiting factor of welded structures in conditions such as marine environments. In this paper, key recent work on welding of HEAs is reviewed in detail focusing on the research of main HEA systems when applying different welding techniques. The experimental details including sample preparation, sample size (thickness) and welding conditions reflecting energy input are summarized and key issues are highlighted. The microstructures and properties of different welding zones, in particular the fusion zone (FZ) and the heat affected zones (HAZ), formed with different welding methods are compared and presented in details and the structure-property relationships are discussed. The work shows that the weldability of HEAs varies with the HEA composition groups and the welding method employed. Arc and laser welding of AlCoCrFeNi HEAs results in lower hardness in the FZ and HAZ and reduced overall strength. Friction stir welding results in higher hardness in the FZ and achieves comparable/higher strength of the welded joints in tensile tests. The welded HEAs are capable of maintaining a reasonable proportion of the ductility. The key structure changes including element distribution, the volume fraction of face centered cubic (FCC) and body centered cubic (BCC) phase as well as reported changes in the lattice constants are summarized and analyzed. Detailed mechanisms governing the mechanical properties including the grain size-property/hardness relationship in the form of Hall–Petch (H–P) effect for both bulk and welded structure of HEAs are compared. Finally, future challenges and main areas to research are highlighted.

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Section: Welding Of Heas In Different Welding Processesmentioning

confidence: 69%

“…Research on laser beam welding (LBW) of HEAs has been reported in several recent publications [ 26 , 27 , 28 , 29 , 30 ]. In a laser welding process, pieces of metal are melted and joined through a concentrated heat source provided by the laser beam, forming a narrow, deep weld ( Figure 4 a).…”

Section: Welding Of Heas In Different Welding Processesmentioning

confidence: 99%

Welding of High Entropy Alloys—A Review

Guo

Tang

Rothwell

et al. 2019

Entropy

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show abstract

“…Several studies [53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][68][69] have already been reported on fusion-based welding of HEAs. To date, these works focus mainly on laser-based techniques, although some information is also available on Electron Beam and Gas Tungsten Arc Welding (GTAW) techniques.…”

Section: Fusion-based Welding Of Heasmentioning

confidence: 99%

“…The influence of post-weld heat treatments on laser welded CoCrFeNiMn HEAs was also reported in the literature. Nam et al [59] studied the effect of post-weld heat treatments on a temperature range of 800 and 1000 • C for one hour, on laser beam welds of a cold-rolled CoCrFeNiMn HEA. Before the heat-treatment, the welded region exhibited a larger grain size and inferior tensile strength and hardness than the BM.…”

Section: Cocrfenimn Hea Systemmentioning

confidence: 99%

A Short Review on Welding and Joining of High Entropy Alloys

Lopes

Oliveira

2020

Metals

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High entropy alloys are one of the most exciting developments conceived in the materials science field in the last years. These novel advanced engineering alloys exhibit a unique set of properties, which include, among others, good mechanical performance under severe conditions in a wide temperature range and high microstructural stability over long time periods. Owing to the remarkable properties of these alloys, they can become expedite solutions for multiple structural and functional applications. Nevertheless, like any other key engineering alloy, their capacity to be welded, and thus become a permanent feature of a component or structure, is a fundamental issue that needs to be addressed to further expand these alloys’ potential applications. In fact, welding of high entropy alloys has attracted some interest recently. Therefore, it is important to compile the available knowledge on the current state of the art on this topic in order to establish a starting point for the further development of these alloys. In this article, an effort is made to acquire a comprehensive knowledge on the overall progress on welding of different high entropy alloy systems through a systematic review of both fusion-based and solid-state welding techniques. From the current literature review, it can be perceived that welding of high entropy alloys is currently gaining more interest. Several high entropy alloy systems have already been successfully welded. However, most research works focus on the well-known CoCrFeMnNi. For this specific system, both fusion and solid-state welding have been used, with no significant degradation of the joints’ mechanical properties. Among the different welding techniques already employed, laser welding is predominant, potentially due to the small size of its heat source. Overall, welding of high entropy alloys is still in its infancy, though good perspectives are foreseen for the use of welded joints based on these materials in structural applications.

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“…There are two primary categories of HEAs: HEAs with a face-centered cubic (FCC) structure [1][2][3][4][5][6][7] and HEAs with a body-centered cubic (BCC) structure [21,22]. Cantor alloy, as a typical form of FCC HEA which is composed of Cr, Mn, Fe, Co, and Ni, has been studied for cryogenic alloys because the alloy has high toughness and strength at low temperature [23]. On the other hand, refractory BCC HEAs, which usually contain Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W, were researched intensively as Metals 2019, 9,1296 2 of 16 high-temperature alloys due to their enhanced mechanical properties at elevated temperatures [11,21].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Spherical V-Nb-Mo-Ta-W High-Entropy Alloy Powder Using Hydrogen Embrittlement and Spheroidization by Thermal Plasma

Lee

Park

et al. 2019

Metals

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V-Nb-Mo-Ta-W high-entropy alloy (HEA), one of the refractory HEAs, is considered as a next-generation structural material for ultra-high temperature uses. Refractory HEAs have low castability and machinability due to their high melting temperature and low thermal conductivity. Thus, powder metallurgy becomes a promising method for fabricating components with refractory HEAs. Therefore, in this study, we fabricated spherical V-Nb-Mo-Ta-W HEA powder using hydrogen embrittlement and spheroidization by thermal plasma. The HEA ingot was prepared by vacuum arc melting and revealed to have a single body-centered cubic phase. Hydrogen embrittlement which could be achieved by annealing in a hydrogen atmosphere was introduced to get the ingot pulverized easily to a fine powder having an angular shape. Then, the powder was annealed in a vacuum atmosphere to eliminate the hydrogen from the hydrogenated HEA, resulting in a decrease in the hydrogen concentration from 0.1033 wt% to 0.0003 wt%. The angular shape of the HEA powder was turned into a spherical one by inductively-coupled thermal plasma, allowing to fabricate spherical V-Nb-Mo-Ta-W HEA powder with a d 50 value of 28.0 µm.

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Effect of post weld heat treatment on weldability of high entropy alloy welds

Cited by 67 publications

References 30 publications

Welding of High Entropy Alloys—A Review

Welding of High Entropy Alloys—A Review

A Short Review on Welding and Joining of High Entropy Alloys

Synthesis of Spherical V-Nb-Mo-Ta-W High-Entropy Alloy Powder Using Hydrogen Embrittlement and Spheroidization by Thermal Plasma

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