Microstructural Analysis of Linear Friction-Welded 718 Plus Superalloy

Vishwakarma, K.R.; Ojo, O.A.; Wanjara, P.; Chaturvedi, M.C.

doi:10.1007/s11837-014-0938-7

Cited by 31 publications

(19 citation statements)

References 27 publications

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“…Qian and Lippold [21] related intergranular HAZ liquation cracking to the combined effects of δ phase dissolution, boron carbide constitutional liquation, and grain boundary segregation. On the other hand, Zhang and Ojo [22,23] reported that the δ phase could actually constitutionally liquate in the HAZ during welding above their solvus (about 1010 • C in IN718) and enrich the grain boundary with Nb. Thrappel et al [24] and Muralidharan et al [25] reported that during rapid heating, second phase eutectic grain boundary precipitates such as γ/Laves or γ/NbC (at 1200 • C) present in the HAZ of wrought IN718 melted due to the lack of time for dissolution into the matrix.…”

Section: Of 20mentioning

confidence: 99%

Microstructure Evolution of Selective Laser Melted Inconel 718: Influence of High Heating Rates

Tabaie

Rézaï-Aria

Jahazi

2020

Metals

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Inconel 718 (IN718) superalloy samples fabricated by selective laser melting (SLM) were submitted to different heating cycles and their microstructural characteristics were investigated. The selected heating rates, ranging from 10 °C/min to 400 °C/s, represent different regions in the heat-affected zone (HAZ) of welded additively manufactured specimens. A combination of differential thermal analysis (DTA), high-resolution dilatometry, as well as laser confocal and electron microscopy were used to study the precipitation and dissolution of the secondary phases and microstructural features. For this purpose, the microstructure of the additively manufactured specimen was investigated from the bottom, in contact with the support, to the top surface. The results showed that the dissolution of γ″ and δ phases were delayed under high heating rates and shifted to higher temperatures. Microstructural analysis revealed that the Laves phase at the interdendritic regions was decomposed in specific zones near the surface of the samples. It was determined that the thickness and area fraction of these zones were inversely related to the applied heating rate. A possible mechanism based on the influence of heating rate on Nb diffusion in the interdendritic regions and core of the dendrites is proposed to interpret the observed changes in the microstructure.

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Section: Of 20mentioning

confidence: 99%

Microstructure Evolution of Selective Laser Melted Inconel 718: Influence of High Heating Rates

Tabaie

Rézaï-Aria

Jahazi

2020

Metals

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“…[4][5][6][7] Friction welding technology does not require filler metal addition or protective gas shielding for joining similar and dissimilar materials. 2,[8][9][10] LFW process offers multiple advantages over other mechanical joining techniques, for example, fusion welding, 8,[11][12][13] as it can effectively avoid the welding defects like hot cracking and it has a lower possibility for the occurrence of dissolution of hardening precipitates 9,10,14 for precipitation-hardened alloys. Metals and thermoplastics have been joined in multiple variations, particularly non-axisymmetric configurations, using LFW in aerospace and automotive industrial applications.…”

Section: Introductionmentioning

confidence: 99%

Thermomechanical modelling for the linear friction welding process of Ni-based superalloy and verification

Okeke

Harrison

Tong

2020

Proceedings of the Institution of Mechanical Engineers, Part L:

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This paper presents a fully coupled thermomechanical model for the linear friction welding process of Inconel-718 nickel-based superalloy by using the finite element method. Friction heat, plastic work, and contact formulation were taken into account for two deformable plastic bodies oscillating relative to each other under large compressive force. The modelling results of the thermal history at the weldline interface and thermal field at a distance away from the rubbing surfaces were compared to instrumented data sourced from related publications for model verification. Optimal linear friction welding process parameters were identified via comparison of weld temperature to the liquidus temperature of Inconel-718 alloy. Comparison of interface temperature showed a consistent range of values above the solidus melting temperature (1250 ℃) and below the liquidus melting temperature (1360 ℃) of Inconel-718 alloy. For the first time, a visible linear friction welding process window is identified using a thermomechanical computational modelling method. Through computational modelling, the influence of welding process parameters on the heat transfer and deformation of weld was systematically investigated.

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“…Information on ATI 718Plus® is more limited. However, it seems likely that both large grain size [48] and high B and P levels in a modified ATI 718Plus® alloy have an impact on weld cracking [32]. The same study also indicated that cracking in Waspaloy was due to the extensive precipitation of inter-and intragranular y'.…”

Section: The Grain Structurementioning

confidence: 98%

“…The chemical composition in general and the presence of Nb and C in particular is important in this context [8,19,28]. However, it has been concluded that a eutectic liquid is not always detrimental for the hot cracking since in some cases it has been shown to heal cracks by backfilling [29][30][31][32]. Some researchers have monitored the grain structure of the weld deposit through variation of the weld process parameters in order to optimize the weldability.…”

Section: The Grain Structurementioning

confidence: 99%

Weldability of Ni-based Superalloys

Andersson¹

2014

8th International Symposium on Superalloy 718 and Derivatives (2014)

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This paper reviews the inherent weldability of precipitation hardening Ni-based superalloys commonly used in structural components of aircraft engines. Weldability often refers to alloys resistant to cracking during welding which for superalloys is difficult to comprehend since specific liquation and cracking mechanism may differ in this class of materials. A new procedure of evaluating the weldability as well as susceptibility towards strain age cracking of these alloys is proposed in which standard metallographic examinations are used to understand the cracking mechanisms in parallel with systematic ductility measurements such as Varestraint or Gleeble testing.

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Microstructural Analysis of Linear Friction-Welded 718 Plus Superalloy

Cited by 31 publications

References 27 publications

Microstructure Evolution of Selective Laser Melted Inconel 718: Influence of High Heating Rates

Microstructure Evolution of Selective Laser Melted Inconel 718: Influence of High Heating Rates

Thermomechanical modelling for the linear friction welding process of Ni-based superalloy and verification

Weldability of Ni-based Superalloys

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