On the Effects of the Rejuvenation Treatment on Mechanical and Microstructural Properties of IN-738 Superalloy

Monti, Cosimo; Giorgetti, Alessandro; Tognarelli, Leonardo; Mastromatteo, Francesco

doi:10.1007/s11665-017-2646-2

Cited by 20 publications

(4 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To lower the life cost during service, less expensive means are developed as an alternative to replace new components. Furthermore, rejuvenation treatments are reported to be able to restore the microstructures and mechanical properties of degraded superalloys [4][5][6]. More often, repair-welding is chosen as the major way to refurbish cracked or damaged blades in gas turbines [1].…”

Section: Introductionmentioning

confidence: 99%

Liquation Cracking in the Heat-Affected Zone of IN738 Superalloy Weld

Chen

Shiue

et al. 2018

Metals

View full text Add to dashboard Cite

Abstract:The main scope of this study investigated the occurrence of liquation cracking in the heat-affected zone (HAZ) of IN738 superalloy weld, IN738 is widely used in gas turbine blades in land-based power plants. Microstructural examinations showed considerable amounts of γ' uniformly precipitated in the γ matrix. Electron probe microanalysis (EPMA) maps showed the γ-γ' colonies were rich in Al and Ti, but lean in other alloy elements. Moreover, the metal carbides (MC), fine borides (M 3 B 2 and M 5 B 3 ), η-Ni 3 Ti, σ (Cr-Co) and lamellar Ni 7 Zr 2 intermetallic compounds could be found at the interdendritic boundaries. The fracture morphologies and the corresponding EPMA maps confirmed that the liquation cracking in the HAZ of the IN738 superalloy weld resulted from the presence of complex microconstituents at the interdendritic boundaries.

show abstract

Section: Introductionmentioning

confidence: 99%

Liquation Cracking in the Heat-Affected Zone of IN738 Superalloy Weld

Chen

Shiue

et al. 2018

Metals

View full text Add to dashboard Cite

show abstract

“…Kwai S. Chan and Giulio Marchese [7,8] predicted crystal growth of Ni-based superalloys Inconel 718 and 718 plus during additive layer-by-layer deposition of laser powder bed fusion process under multi-variant heat treatments. Adelajda Polkowska, Cosimo Monti and I. Guzman [9][10][11] discussed influence of rejuvenation heat treatment cooling conditions on crystal growth of gamma phase, size and distribution of gamma prime phase of Ni-based superalloys Haynes 282 and Inconel738. Fan Yang and Y.F.…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis Nucleation and Growth Conditions of Single-Crystallinity Control during Laser Surface Modification of Ni-Based Single-Crystal Superalloy Part I: Thermal and Chemical Determinants

Gao

2022

SSP

View full text Add to dashboard Cite

Nucleation and growth conditions of single-crystallinity control are convincingly elaborated by multi-scale mathematical modeling of heat and mass transport to totally abate undesirable weld defects, e.g. disoriented crystal and hot cracking inside molten pool of nonequilibrium crystallization, in order to illustrate the usefulness of predictive capability through theory and experiment procedures. Crystal growth is complicated by crystallinity-dependent thermal and chemical driving forces in front of dendrite tip during viable laser surface modification of Ni-based single-crystal superalloy. These two thermal metallurgical determinants play crucial role in crack-insusceptible columnar crystal growth, which is favorably oriented throughout weld depth. There is particular challenge in complete elimination of disoriented crystal, i.e. stray grain formation, for acceptable surface quality. Conservative (001)/[100] crystalline orientation is desired to diminish Al concentration and supersaturation, and morphologically satisfy epitaxial growth kinetics to successfully lessen central cracking with satisfactory variability of laser power and welding speed. Comparatively, (001)/[110] crystalline orientation is disadvantageous to asymmetrically augment Al concentration and supersaturation and aggressively increase interface instability, microstructure heterogeneity and hot cracking vulnerability along disoriented crystal boundaries. Disoriented crystal is increasingly withstood if the Al concentration and supersaturation in front of dendrite tip are low enough and crack-unsusceptible part is relatively large enough in case of attractive (001)/[100] crystalline orientation with optimal range of heat input to ameliorate microstructure homogeneity. Crystalline orientation region varies with diverse welding configurations, and epitaxy across solid/liquid interface is also sensitive to heat input of laser processing, which necessitate high efficient welding conditions optimization. Considerable effort is made to distinguish diffusion-driven crystal growth between a series of combinations of multiple welding conditions, such as critical welding configuration and heat input. Metallographically, the morphologies of crystal growth and hot cracking are experimentally observed to consistently support kinetics calculation result and well explain correlation between solidification behavior and crystal growth.

show abstract

“…[2,37,42,43] For applications that require higher thermal stability typically IN 738 is used. A disadvantage of this alloy is the poor weldability due to the high volume fraction [44] (about 40%) of the fine dispersed γ 0 precipitates, which makes repair processes more challenging.…”

Section: Introductionmentioning

confidence: 99%

Thermal Spray Processes for the Repair of Gas Turbine Components

et al. 2020

View full text Add to dashboard Cite

Gas turbine components are often operated in harsh conditions, which can lead to severe damage. As it is highly desirable from both an economical and an ecological point of view to restore these worn areas instead of manufacturing new components, repair technologies are of huge interest for companies supplying maintenance and overhaul of gas turbines. In this article, two thermal techniques are described that can be used for this application: cold gas spraying (CGS) and vacuum plasma spraying (VPS). The CGS process allows the deposition of metallic coatings with excellent mechanical properties; several examples including γ-TiAl, Inconel (IN) 718, and IN 738 are given. Essential for the deposition of high-performance coatings in CGS is to exceed the so-called critical velocity. This is discussed also with experimental findings. As a final topic, experiments that use VPS for the repair of single-crystal alloys are described.

show abstract

On the Effects of the Rejuvenation Treatment on Mechanical and Microstructural Properties of IN-738 Superalloy

Cited by 20 publications

References 21 publications

Liquation Cracking in the Heat-Affected Zone of IN738 Superalloy Weld

Liquation Cracking in the Heat-Affected Zone of IN738 Superalloy Weld

Numerical Analysis Nucleation and Growth Conditions of Single-Crystallinity Control during Laser Surface Modification of Ni-Based Single-Crystal Superalloy Part I: Thermal and Chemical Determinants

Thermal Spray Processes for the Repair of Gas Turbine Components

Contact Info

Product

Resources

About