The effect of near-surface plastic deformation on the hot corrosion and high temperature corrosion-fatigue response of a nickel-based superalloy

Cockings, Hollie; Cockings, B.J.; Harrison, W. J.; Dowd, Michael F.; Perkins, Karen; Whittaker, Mark; Gibson, Grant J.

doi:10.1016/j.jallcom.2020.154889

Cited by 29 publications

(6 citation statements)

References 18 publications

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“…Turbine blades in particular are prone to damaging effects from hot corrosion fatigue due to the high-temperature combustion products that they are in contact with during operation [31]. SP [60,61] and LP [62,63] have been studied for their ability to reduce crack growth and thus slow hot corrosion fatigue. Figure 7a,b show cross-sectional SEM images of untreated and LPed single crystal Ni-based superalloy specimens along with corresponding energy dispersive spectroscopy (EDS) data following a hot corrosion test [52].…”

Section: Mechanical Property Evolutionmentioning

confidence: 99%

A Review of Laser Peening Methods for Single Crystal Ni-Based Superalloys

Holtham

Davami

2022

Metals

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Single crystal Ni-based superalloys are often used to create gas turbine engine blades for their high strength under intense thermo-mechanical loading. Though they are remarkably capable under these conditions, a particular class of premature failure mechanisms known as surface-initiated damage mechanisms can lead to the early fracture of an otherwise healthy blade. This review paper discusses the current progress of post-processing techniques that can greatly mitigate the potency of surface-initiated damage mechanisms. In particular, laser peening (LP) is of significant interest due to the relatively low amount of cold work it induces, greater depth of compressive residual stresses than other cold working methods, ability to accommodate complex part geometries, and the minuscule effect it has on surface roughness. The residual stresses imparted by LP can greatly hinder crack growth and consequently allow for enhanced fatigue life. Given that turbine blades (constructed with single crystal Ni-based superalloys) are prone to fail by these mechanisms, LP could be a worthy choice for increasing their service lives. For this reason, initiative has been taken to better understand the mechanical and microstructural modifications imparted by LP on single crystal Ni-based superalloys and a summary of these investigations are presented in this review. Results from several works show that this class of alloy responds well to LP treatment with improvements such as ~30–50% increase in microhardness, 72% increase in low cycle fatigue life, and elevated resistance to hot corrosion. The primary objective of this review is to provide insight into current state-of-the-art LP techniques and summarize the findings of numerous works which have utilized LP for increasing the service lives of single crystal Ni-based superalloy components.

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Section: Mechanical Property Evolutionmentioning

confidence: 99%

A Review of Laser Peening Methods for Single Crystal Ni-Based Superalloys

Holtham

Davami

2022

Metals

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“…Hot corrosion exists as Type I (known as High-Temperature Hot Corrosion) or Type II (Low-Temperature Hot Corrosion), with the former occurring above 800-950°C and the latter at 600-750°C [88,89]. The occurrence of either attack form is dependent on several parameters such as the composition of the alloy, contaminant, and gas.…”

Section: Characteristicsmentioning

confidence: 99%

“…Nb is one element used in many research works [86][87][88][89][90] to improve the oxidation resistance of TiAl alloys. Al activities are promoted by Nb additions and accelerate protective Al 2 O 3 oxide film formation, limiting oxygen diffusion into the alloy [166].…”

Section: Effect Of Alloy Modifications On the Oxidation Resistance Of Tialmentioning

confidence: 99%

Hot Corrosion and Oxidation Behaviour of TiAl Alloys during Fabrication by Laser Powder Bed Additive Manufacturing Process

Mogale¹,

Matizamhuka²,

Cobbinah³

2022

Corrosion - Fundamentals and Protection Mechanisms

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This research paper summarises the practical relevance of additive manufacturing with particular attention to the latest laser powder bed fusion (L-PBF) technology. L-PBF is a promising processing technique, integrating intelligent and advanced manufacturing systems for aerospace gas turbine components. Some of the added benefits of implementing such technologies compared to traditional processing methods include the freedom to customise high complexity components and rapid prototyping. Titanium aluminide (TiAl) alloys used in harsh environmental settings of turbomachinery, such as low-pressure turbine blades, have gained much interest. TiAl alloys are deemed by researchers as replacement candidates for the heavier Ni-based superalloys due to attractive properties like high strength, creep resistance, excellent resistance to corrosion and wear at elevated temperatures. Several conventional processing technologies such as ingot metallurgy, casting, and solid-state powder sintering can also be utilised to manufacture TiAl alloys employed in high-temperature applications. This chapter focuses on compositional variations, microstructure, and processing of TiAl alloys via L-PBF. Afterward, the hot corrosion aspects of TiAl alloys, including classification, characteristics, mechanisms and preventative measures, are discussed. Oxidation behaviour, kinetics and prevention control measures such as surface and alloy modifications of TiAl alloys at high temperature are assessed. Development trends for improving the hot corrosion and oxidation resistance of TiAl alloys possibly affecting future use of TiAl alloys are identified.

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“…It is clear that even after a relatively short 50 h trial (typical stress free hot corrosion trials have previously lasted between 200 and 500 h [3]) the quantity of chloride had a greater effect on the hot corrosion behaviour of FG RR1000 than the choice of cation (potassium vs sodium). To date, work on type II hot corrosion of Ni-based alloys has typically investigated the effects of applying 98%Na 2 SO 4 -2%NaCl [14,15,23,[25][26][27][28], with several studies investigating pure Na 2 SO 4 [29] and 80%Na 2 SO 4 -20%K 2 SO 4 [24] at 700 • C. 700 • C has frequently been the chosen temperature for hot corrosion trials due to its link with the greatest corrosion rates under type II conditions as per the classic 'double-bell curve' [30]. The choice of 600 • C in this study allows the investigation of both lower temperature chloride-based mechanisms and type II hot corrosion (albeit not at the most damaging rate).…”

Section: Stress-free Hot Corrosionmentioning

confidence: 99%