High-temperature low-cycle fatigue of an iron-base oxide-dispersion strengthened alloy: Grain structure effects and lifetime correlations

Banhardt, V.; Nader, Marc-Elie; Arzt, Eduard

doi:10.1007/bf02670602

Cited by 12 publications

(4 citation statements)

References 10 publications

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“…At present, the knowledge of LCF behaviour of ODS steels is limited since only few studies were dedicated to this issue. [8][9][10][11][12][13][14][15] However, these few studies successfully demonstrate the significance of oxide dispersion strengthening with respect to the cyclic properties. In comparison with the non-ODS variants, the ODS steels offer higher cyclic stress levels with significantly lower inelastic strain amplitudes.…”

Section: Introductionmentioning

confidence: 99%

“…This stability can be judged by straining material cyclically in the regime of elastic‐plastic loading, which yields low‐cycle fatigue (LCF). At present, the knowledge of LCF behaviour of ODS steels is limited since only few studies were dedicated to this issue . However, these few studies successfully demonstrate the significance of oxide dispersion strengthening with respect to the cyclic properties.…”

Section: Introductionmentioning

confidence: 99%

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Towards improved ODS steels: A comparative high‐temperature low‐cycle fatigue study

Chauhan

Walter

Aktaa

2017

Fatigue Fract Eng Mat Struct

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Within the frame of this work, the mechanical behaviour of a bimodal ferritic 12Cr‐ODS steel as well as of a ferritic‐martensitic 9Cr‐ODS steel under alternating load conditions was investigated. In general, strain‐controlled low‐cycle fatigue tests at 550°C and 650°C revealed similar cyclic stress response. At elevated temperatures, the two steels manifest transitional stages, ie, cyclic softening and/or hardening corresponding to the small fraction of the cyclic life, which is followed by a linear cyclic softening stage that occupies the major fraction of the cyclic life until failure. However, it is clearly seen that the presence of the nano‐sized oxide particles is certainly beneficial, as the degree of cyclic softening is significantly reduced compared with non‐ODS steels. Besides, it is found that both applied strain amplitude and testing temperature show a strong influence on the cyclic stress response. It is observed that the degree of linear cyclic softening in both steels increases with increasing strain amplitude and decreasing test temperature. The effect of temperature on inelastic strain and hence lifetime becomes more pronounced with decreasing applied strain amplitude. When analysing the lifetime behaviour of both ODS steels in terms of inelastic strain energy calculations, it is found that comparable inelastic strain energies lead to similar lifetimes at 550°C. At 650°C, however, the higher inelastic strain energies of 12Cr‐ODS steel result in significant lower lifetimes compared with those of the 9Cr‐ODS steel. The strong degradation of the cyclic properties of the 12Cr‐ODS steel is obviously linked to the fact that the initial hardening response appears significantly more pronounced at 650°C than at 550°C. Finally, the obtained results depict that the 9Cr‐ODS steel offers higher number of cycles to failure at 650°C, compared with other novel ODS steels described in literature.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Towards improved ODS steels: A comparative high‐temperature low‐cycle fatigue study

Chauhan

Walter

Aktaa

2017

Fatigue Fract Eng Mat Struct

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“…Consequently, this highlights the major importance of the grain aspect ratio (GAR) in this class of alloys (3) Additionally, fine equiaxed grains -so called "recystallization defects" -are present in the material which may -depending on their volume fraction -further weaken the materials deformation resistance (3)(4)(5). While the creep resistance of these ODS nickel-base superalloys is known to be outstanding -even superior to that of single crystal superalloys at temperatures around and beyond 1OOO'Conly a few reports deal with their low cycle fatigue (LCF) behavior (6,7).…”

Section: Introductionmentioning

confidence: 99%

The Effect of Strain Rate and Temperature on the LCF Behavior of the ODS Nickel-Base Superalloy PM 1000

Heilmaier¹,

Nganbe²,

Müller³

et al. 2000

Superalloys 2000 (Ninth International Symposium)

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The high temperature LCF behavior of the oxide dispersion strengthened (ODS) nickel-base superalloy PM 1000 was studied using single-step tests with constant total strain amplitudes ranging from 0.2 to 0.7%. Specifically, the effect of varying strain rate and temperature on the cyclic lifetimes as well as on the fatigue crack initiation and propagation was studied. It was found that a decrease of the applied strain rate by a factor of 100 drastically reduces cyclic lifetime whereas an increase of temperature by 150 K decreases Nf only moderately. This behavior can be qualitatively understood on the basis of post-mortem microstructural investigations of fatigued specimens which reveal pronounced void formation and coalescence at transverse grain boundaries followed by cleavage at longitudinal grain boundaries leading to failure.

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“…Banhardt et al 5 concluded that in total strain controlled tests, the cyclic lifetime can be mainly correlated with Young's modulus in the loading direction and not with the grain structure or, more precisely, with the GAR value.…”

Section: Introductionmentioning

confidence: 99%

The role of grain structure in the creep and fatigue of ni-based superalloy PM 1000

Heilmaier

Müller

1999

JOM

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High-temperature low-cycle fatigue of an iron-base oxide-dispersion strengthened alloy: Grain structure effects and lifetime correlations

Cited by 12 publications

References 10 publications

Towards improved ODS steels: A comparative high‐temperature low‐cycle fatigue study

Towards improved ODS steels: A comparative high‐temperature low‐cycle fatigue study

The Effect of Strain Rate and Temperature on the LCF Behavior of the ODS Nickel-Base Superalloy PM 1000

The role of grain structure in the creep and fatigue of ni-based superalloy PM 1000

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