Effect of post-weld heat treatments on microstructure and mechanical properties of friction welded alloy 718 joints

Damodaram, R.; Raman, S. Ganesh Sundara; Rao, K. Prasad

doi:10.1016/j.matdes.2013.07.091

Cited by 50 publications

(12 citation statements)

References 22 publications

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“…Specifically, the LFW of additively manufactured Inconel 718 (IN718) to forged AD730 TM Ni-based superalloy is investigated. IN718 is a high strength superalloy extensively used for blade applications in gas turbines due to its good weldability and excellent resistance to cracking [20][21][22]. AD730 TM is a Ni-based alloy recently developed by Auber & Duval Company as a new forged Ni-based superalloy for turbine disk applications, and its mechanical properties are comparable to those of other Ni-based superalloys such as Waspaloy, Udimet720 and IN718Plus [13,14,[23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Grain size and misorientation evolution in linear friction welding of additively manufactured IN718 to forged superalloy AD730™

Tabaie

Rézaï-Aria²,

Flipo³

et al. 2021

Materials Characterization

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Selective Laser Melted (SLM) Inconel718 (IN718) superalloy was linear friction welded (LFWed) to forged AD730 TM Nickel-based superalloy. Successful joints free of micro-porosity, micro-cracking, and oxides were obtained. Microstructure variations across the weld line developed during LFW were examined using different techniques, including laser confocal microscopy, scanning electron microscopy, energy dispersive spectroscopy (EDS) and electron backscatter diffraction (EBSD). The microstructure was also evaluated, particularly in terms of Grain size and misorientation changes were determined and correlated with microhardness evolution in different regions of the weld joint. The characteristics of the microstructure on both sides of the weld joint was analyzed and related to the deformation and temperature paths imposed during the LFW process. Dynamic recrystallization (DRX) occurred on both sides of the dissimilar weld line and it was found that Discontinuous DRX (DDRX) and Continuous DRX (CDRX) took place in the WZ and in the TMAZ, respectively. In order to study the influence of the starting microstructure in the LFW experiments, LFW of a homogenized SLM IN718 sample was analyzed and compared with the non-homogenized sample. A clear change in the size and grain misorientation levels of the heat and thermomechanical affected zones were observed between the two conditions. The differences were related to a greater degree of strain induced in homogenized sample and the increasing effect of the solid solution strengthening mechanism caused by a partial dissolution of the second-phase strengthening particles in the matrix.

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Section: Introductionmentioning

confidence: 99%

Grain size and misorientation evolution in linear friction welding of additively manufactured IN718 to forged superalloy AD730™

Tabaie

Rézaï-Aria²,

Flipo³

et al. 2021

Materials Characterization

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“…The dynamic and post-dynamic recrystallization, as well as the dissolution of creep resisting phases during welding, are expected to have some adverse effects on creep properties [2,10,11]. Damodaram et al reported that, a reduction in the average size and volume fraction of γ´ precipitates led to a reduction in the mechanical properties of as-welded specimens [12]. They studied the tensile properties of as-weld and post-weld heat-treated (PWHT) conditions on continuous drive friction-welded Inconel 718 specimens.…”

Section: Introductionmentioning

confidence: 99%

High temperature creep properties of a linear friction welded newly developed wrought Ni-based superalloy

Masoumi

Thébaud

Shahriari

et al. 2018

Materials Science and Engineering: A

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AD730 TM Ni-based superalloy specimens in solution-treated conditions were linear friction welded. Then, post-weld heat treatment (PWHT), consisting of γ´ sub-solvus solution treatments followed by aging, was conducted on the linear friction welded samples. High temperature creep tests were performed on the as-welded and PWHTed joints at two different temperatures: 700°C under 600 and 750 MPa stress levels, and 850°C under 100 and 200 MPa stresses. The creep resistance of the PWHTed joints was higher than that of the as-welded samples. The PWHTed joints exhibited better ductility than that of the base material at 850°C, while they showed slightly lower creep life at 700°C in comparison to the base metal. Microstructure examination showed that cracks initiated at the interface of oxidized particles at 700°C. The decrease in creep resistance of the AD730 TM Ni-based superalloy at 850°C was related to a combination of the formation of precipitate-free zones (PFZ) in the vicinity of the grain boundaries (GBs) and microcracking assisted by oxidation. The Larson-Miller Parameter (LMP) was used to correlate the creep strength, temperature and time to failure for the as-welded and PWHTed samples. LMP values varied between 21.5×10 3 and 24.5×10 3. It was found that in the investigated temperature range, the PWHTed AD730 TM has similar creep characteristics as Udimet TM 720 Li and Inconel 738LC at low values of LMP and better creep properties than those of the Inconel 617 alloy at higher LMP values.

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“…The turbine blade foot reaches 700 °C and the tensile stress can reach to 500 MPa. Inconel 718 can be welded by various fusion welding methods [1].…”

Section: Introductionmentioning

confidence: 99%

The Effect of TIG Welding Parameters and Automatization for Non-Heat Treated Inconel 718 Sheets

2021

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Inconel 718 alloy is widely used in applications that require advanced strength properties especially at high temperature conditions. Combust room walls, exhaust parts, jet tribune blades and gas tribune equipment are the most known using areas. This alloy can be welded with various fusion welding methods, but TIG (Tungsten Inert Gas) welding is preferred since, it provides simply application, mobility and low cost. This study was aimed to clarify that how adjusting the welding parameters and welding automatically can help to achieve promising mechanical properties before heat treatments. The welding experiments were conducted on three different welding current values and attention was paid to provide full penetration for each condition. The results showed that the highest welding current value which did not cause welding defects lead to decrease heat input due to the high transverse speed usage. Moreover, by automatically welding, the heat input was decreased to a minimum level that provided excellent tensile strength and elongation properties. Dendrites turned to cellular from colon. Hazardous zones, such as HAZ and PMZ, narrowed down. The Laves phase ratio and grain size also decreased. Microhardness results confirmed these microstructure observations. The crack observations after tensile tests showed that failures were near HAZ in high-heat input conditions. However, failures were observed in FZ for low-heat input conditions. Additionally, ductile fracture and fracture similar to cleavage mechanisms were observed together due to adjusting the parameters and automatization.

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Effect of post-weld heat treatments on microstructure and mechanical properties of friction welded alloy 718 joints

Cited by 50 publications

References 22 publications

Grain size and misorientation evolution in linear friction welding of additively manufactured IN718 to forged superalloy AD730™

Grain size and misorientation evolution in linear friction welding of additively manufactured IN718 to forged superalloy AD730™

High temperature creep properties of a linear friction welded newly developed wrought Ni-based superalloy

The Effect of TIG Welding Parameters and Automatization for Non-Heat Treated Inconel 718 Sheets

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