Surface nano-hardness and microstructure of a single crystal nickel base superalloy after laser shock peening

Lu, Guoxin; Liu, J.D.; Qiao, Hongchao; Zhou, Yu; Jin, Tao; Zhao, Jierong; Sun, Xiangfei; Hu, Z. Q.

doi:10.1016/j.optlastec.2016.12.032

Cited by 22 publications

(5 citation statements)

References 19 publications

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“…Instead, the once cuboidal microstructure deforms into a less regular arrangement with heavily compressed γ' surrounding the impact site (Figure 5a). As the pressure wave causes local distortions of the γ/γ' microstructure, the γ' precipitates are compressed normal to the direction of LP and the softer γ phase is pushed from the vertical channels into the horizontal channels [59] (Figure 6a,b). This precipitate morphology change was also noted by Tang et al [48] who used the change in side length of γ' phases as a secondary metric to determine the effectiveness of their modified LP treatment.…”

Section: Microstructure Modifications Resulting From Lpmentioning

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: Microstructure Modifications Resulting From Lpmentioning

confidence: 99%

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

Holtham

Davami

2022

Metals

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“…The performance requirements of aero engines are gradually increasing, and the question of how to further enhance the high-temperature strength of materials to achieve fatigue longevity has become the focus of research in various countries. The author has taken the lead in research related to the use of LSP technology to strengthen a Ni-based single-crystal superalloy for engine blades (Figure 5) and systematically studied the variations in surface integrity parameters, including the surface topography, microstructure and nano-hardness, of the (001) crystal planes of experimental alloys subjected to LSP treatment [47,48]. The authors’ related research revealed the effect of LSP on the medium-/high-temperature tensile behaviour of [001] oriented Ni-based single-crystal superalloys (Figure 6) [49], paving the way for the analysis of the LSP strengthening mechanism of anisotropy single-crystal alloys.…”

Section: Lsp Requirements For Turbine Tenon Joint Materialsmentioning

confidence: 99%

Improving the fretting performance of aero-engine tenon joint materials using surface strengthening

Liu

Lin

et al. 2019

Materials Science and Technology

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This paper summarises the regulation mechanism of the traditional and emerging surface strengthening treatments – mechanical shot peening (SP) and laser shock processing (LSP) treatment, respectively – on the fretting fatigue behaviour of the tenon joint materials of aero-engine cold-end parts, as surface strengthening treatment contributes to the improvement of service performance. From the point of view of the actual service environment of turbine components, this paper also expounds on the key problems faced by surface strengthening treatments in improving the mechanical properties of joint materials for aero-engine hot-end components. The application of LSP in the fretting fatigue life extension of turbine joint materials has strong feasibility and development prospects.

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“…Both surface hardening techniques have been applied to a wide range of alloys and ceramics [12]. However, in comparison with other materials, the surface hardening of Ni-based single-crystal superalloys has received relatively little attention, both in LSP [13][14][15][16][17][18][19][20][21] and in MSP [22,23]. Further understanding of their effect on the surface properties, cold work and performance of these superalloys is still required.…”

Section: Introductionmentioning

confidence: 99%

Effects of surface hardening by laser shock peening and shot peening on a nickel-based single-crystal superalloy CMSX-4

Hakeem,

Morar,

Dawson

et al. 2024

Mater. Res. Express

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Improving the expected life of nickel-based single-crystal superalloy turbine components by surface hardening treatments including laser shock peening (LSP) and mechanical shot peening (MSP) are of particular interest for mitigation of life limiting damage such as environmental assisted cracking in hot section components of gas turbines. In the present study the effects of LSP and MSP on the surface roughness, microhardness and work hardening of a nickel-based single crystal superalloy CMSX-4® have been assessed. Surface roughness was measured using laser profilometry. The degree of work hardening was measured using electron backscattered diffraction with local misorientation analysis. The analysis showed evidence for a work hardening layer in the MSP sample to a depth of approximately 70 m. Sets of slip bands extending far into the bulk of the sample were observed in the LSP-treated sample, without any evidence of a work hardening layer. Microhardness measurements used to gauge the depth of residual stress showed that LSP produced a much deeper hardness profile than MSP, with compressive residual stress depths of 1000 µm and 200 µm in LSP and MSP respectively. The retention of hardness after a heat treatment of 50 h at 700 °C was more prominent in the LSP sample than in the MSP sample. LSP and MSP have therefore been shown to be at the opposite ends of the spectrum of surface hardening treatments of CMSX-4, with LSP giving milder hardening, but to a greater depth. 

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Surface nano-hardness and microstructure of a single crystal nickel base superalloy after laser shock peening

Cited by 22 publications

References 19 publications

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

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

Improving the fretting performance of aero-engine tenon joint materials using surface strengthening

Effects of surface hardening by laser shock peening and shot peening on a nickel-based single-crystal superalloy CMSX-4

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