Effect of base metal and welding speed on fusion zone microstructure and HAZ hot-cracking of electron-beam welded Inconel 718

Mei, Yunpeng; Liu, Yongchang; Liu, Chenxi; Li, Chong; Yu, Liming; Guo, Qianying; Li, Huijun

doi:10.1016/j.matdes.2015.10.082

Cited by 116 publications

(20 citation statements)

References 40 publications

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“…During the heating cycles of welding, the low-melting-point Laves phase at grain boundaries can be liquated, forming grain boundary liquid. With the development of thermal stress during the cooling cycles of welding, the liquated grain boundaries are easily torn apart, leading to the hot cracks/miscrofissures [33,34].…”

Section: Inconel 718mentioning

confidence: 99%

Additively Manufactured Inconel 718 : Microstructures and Mechanical Properties

Deng

2018

Linköping Studies in Science and Technology. Licentiate Thesis

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Linköping 2018Cover image: A fracture surface of EBM IN718 after tensile test at room temperature.During the course of research underlying this thesis, Dunyong Deng was enrolled in Agora Materiae, a multidiciplinary doctoral program at Linköping University, Sweden. Printed by LiU-Tryck 2018 © Dunyong Deng AbstractAdditive manufacturing (AM), also known as 3D printing, has gained significant interest in aerospace, energy, automotive and medical industries due to its capabilities of manufacturing components that are either prohibitively costly or impossible to manufacture by conventional processes. Among the various additive manufacturing processes for metallic components, electron beam melting (EBM) and selective laser melting (SLM) are two of the most widely used powder bed based processes, and have shown great potential for manufacturing high-end critical components, such as turbine blades and customized medical implants. The futures of the EBM and SLM are doubtlessly promising, but to fully realize their potentials there are still many challenges to overcome.Inconel 718 (IN718) is a nickel-base superalloy and has impressive combination of good mechanical properties and low cost. Though IN718 is being mostly used as a turbine disk material now, the initial introduction of IN718 was to overcome the poor weldability of superalloys in 1960s, since sluggish precipitation of strengthening phases γ ′ /γ ′′ enables good resistance to strain-age cracking during welding or post weld heat treatment. Given the similarity between AM and welding processes, IN718 has been widely applied to the metallic AM field to facilitate the understandings of process-microstructure-property relationships.The work presented in this licentiate thesis aims to better understand microstructures and mechanical properties EBM and SLM IN718, which have not been systematically investigated. Microstructures of EBM and SLM IN718 have been characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM) and correlated with the process conditions. Monotonic mechanical properties (e.g., Vickers microhardness and tensile properties) have also been measured and rationalized with regards to the microstructure evolutions before and after heat treatments.For EBM IN718, the results show the microstructure is not homogeneous but dependant on the location in the components, and the anisotropic mechanical properties are probably attributed to alignment of porosities rather than texture.iii Post heat treatment can slightly increase the mechanical strength compared to the as-manufactured condition but does not alter the anisotropy. SLM IN718 shows significantly different microstructure and mechanical properties to EBM IN718. The as-manufactured SLM IN718 has very fine dendritic microstructure and Laves phases in the interdendrites, and is "work-hardened" by the residual strains and dislocations present in the material. Mechanical properties are different between horizontally and vertically built samples, and heat treatment can m...

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Section: Inconel 718mentioning

confidence: 99%

Additively Manufactured Inconel 718 : Microstructures and Mechanical Properties

Deng

2018

Linköping Studies in Science and Technology. Licentiate Thesis

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“…Saxena compared GMAW (gas metal arc welding) with EBW and concluded that the latter technique took significantly less time and number of passes for welding 150-mm-thick stainless steel (i.e., 27 min and single pass for EBW as compared to 4 h and 35 min and 35 passes for GMAW) [24]. EBW has also been used to produce good-quality welds for high-performance Ni-based alloys, Ti2AlNb-and NiTi-based shape memory alloys [25][26][27]. A detailed review of EBW, in terms of techniques, its modern trends and applications, is given by Weglowski et al [28].…”

Section: Welding Of Titanium and Its Alloysmentioning

confidence: 99%

Influence of welding process on the properties of dissimilar titanium alloy weldments: a review

Junaid

Cheema

2020

JMST Adv.

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The extensive use of titanium alloys in a variety of complex industrial applications may be attributed to their properties of high strength-to-weight ratio, corrosion resistance and high temperature strength. Recently, the use of dissimilar titanium alloys has become popular to achieve contrasting characteristics in a single unit. In the fabrication of the structures, joining methods such as welding hold the key in the attainment of the desired characteristics. The present study is aimed at reviewing various state-of-the-art processes used for welding of dissimilar titanium alloys. In particular, the influence of different welding methods such as gas tungsten arc welding (GTAW), laser and electron beam welding on the microstructure, mechanical properties and other characteristics of dissimilar weldments of α, α + β and β titanium alloys has been emphasized. The underlying phenomena that govern the effect of weld processing parameters on the mechanical strength, microstructure and weld joint quality of the alloys were exploited. Moreover, detailed investigations on the fusion zone porosities and evolution of intermetallic concept at the interfacial regions have been examined. Furthermore, different remedial approaches to enhance the joint quality such as beam offsetting, process hybridization, aging and post-weld heat treatments are investigated thoroughly. The latest trends in dissimilar welding of titanium alloys to upheave further research in this area have been reported in the context of their application in industrial applications.

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Section: Inconel 718mentioning

confidence: 99%

On the Microstructures and Anisotropic Mechanical Behaviours of Additively Manufactured IN718

Deng

2019

Linköping Studies in Science and Technology. Dissertations

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Additive manufacturing (AM), also known as 3D printing, offers great design flexibility for manufacturing components with complex geometries, and has attracted significant interest in the aero and energy industries in the past decades. Among the commercial AM processes, selective laser melting (SLM) and electron beam melting (EBM) are the two most widely used ones for metallic materials. Inconel 718 (IN718) is a nickel-base superalloy and has impressive combination of good mechanical properties, weldability and low cost. Due to its excellent weldability, IN718 has been intensively applied in the AM filed, to gain more understanding of the AM processes and fully realize AM's potentials. The study objects in the present thesis include both EBM and SLM IN718. The solidification conditions in EBM and SLM are very different and are different to that of conventional cast, leading to unique microstructures mechanical properties. Therefore, this thesis aims to gain better understanding of the microstructures and anisotropic mechanical behaviours of both EBM and SLM IN718, by detailed characterizations and by comparisons with the forged counterpart. The as-built microstructure of EBM IN718 is spatially dependent: the periphery (contour) region has a mixture of equiaxed and columnar grains, while the bulk (hatch) region has columnar grains elongated along the building direction; the last solidified region close to the top sample surface shows segregation and Laves phases, otherwise the rest of the whole sample is well homogenized. Differently, the as-built microstructure of SLM IN718 is spatially homogeneous: the grains is rather equiaxed and with subgrain cell structures. These microstructures also respond differently to the standard heat treatment routines for the conventional counterparts. Anisotropic mechanical properties are evident in the room temperature tensile tests and high temperature dwell-fatigue tests. The anisotropic tensile properties of EBM IN718 at room temperature are more likely due to the directional alignment of porosities along the building direction rather than the strong crys-In these papers I have been the main contributor, performing all the experimental work, characterization, analysis and manuscript writing, under the supervision of Johan Moverare and Ru Lin Peng.

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Effect of base metal and welding speed on fusion zone microstructure and HAZ hot-cracking of electron-beam welded Inconel 718

Cited by 116 publications

References 40 publications

Additively Manufactured Inconel 718 : Microstructures and Mechanical Properties

Additively Manufactured Inconel 718 : Microstructures and Mechanical Properties

Influence of welding process on the properties of dissimilar titanium alloy weldments: a review

On the Microstructures and Anisotropic Mechanical Behaviours of Additively Manufactured IN718

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