Publication detail

Initiation of fatigue cracks and lifetime of Ni-base superalloys at high mean stress and temperature

KUNZ, L. HORNÍK, V. HUTAŘ, P. FINTOVÁ, S.

Original Title

Initiation of fatigue cracks and lifetime of Ni-base superalloys at high mean stress and temperature

English Title

Initiation of fatigue cracks and lifetime of Ni-base superalloys at high mean stress and temperature

Type

journal article - other

Language

en

Original Abstract

The effect of high-frequency cycling (120 Hz) superimposed on high tensile mean stress on a lifetime of cast Ni-base superalloys IN 713LC at 800 °C and MAR-M 247 at 900 °C was investigated. It has been found that both the alloys exhibit qualitatively similar behavior in creep/fatigue loading conditions. Superposition of small stress amplitudes on the tensile mean stress does not influence the time to fracture until the stress amplitude reaches a threshold value, which is dependent on the mean stress. The higher the mean stress the higher is the stress amplitude threshold value. The observed creep/fatigue behavior is governed by two mechanisms: (a) formation and growth of intergranular cracks by creep mechanism (b) initiation and growth of fatigue cracks from the intergranular creep cracks. The casting defects do not play any important role as regards the lifetime under investigated loading conditions.

English abstract

The effect of high-frequency cycling (120 Hz) superimposed on high tensile mean stress on a lifetime of cast Ni-base superalloys IN 713LC at 800 °C and MAR-M 247 at 900 °C was investigated. It has been found that both the alloys exhibit qualitatively similar behavior in creep/fatigue loading conditions. Superposition of small stress amplitudes on the tensile mean stress does not influence the time to fracture until the stress amplitude reaches a threshold value, which is dependent on the mean stress. The higher the mean stress the higher is the stress amplitude threshold value. The observed creep/fatigue behavior is governed by two mechanisms: (a) formation and growth of intergranular cracks by creep mechanism (b) initiation and growth of fatigue cracks from the intergranular creep cracks. The casting defects do not play any important role as regards the lifetime under investigated loading conditions.

Keywords

IN 713LC MAR-M247 creep/fatigue loading time to fracture defects

Released

12.12.2017

Publisher

Elsevier Ltd

Pages from

44

Pages to

49

Pages count

6

URL

BibTex


@article{BUT152036,
  author="Ludvík {Kunz} and Vít {Horník} and Pavel {Hutař} and Stanislava {Fintová}",
  title="Initiation of fatigue cracks and lifetime of Ni-base superalloys at high mean stress and temperature",
  annote="The effect of high-frequency cycling (120 Hz) superimposed on high tensile mean stress on a lifetime of cast Ni-base superalloys IN 713LC at 800 °C and MAR-M 247 at 900 °C was investigated. It has been found that both the alloys exhibit qualitatively similar behavior in creep/fatigue loading conditions. Superposition of small stress amplitudes on the tensile mean stress does not influence the time to fracture until the stress amplitude reaches a threshold value, which is dependent on the mean stress. The higher the mean stress the higher is the stress amplitude threshold value. The observed creep/fatigue behavior is governed by two mechanisms: (a) formation and growth of intergranular cracks by creep mechanism (b) initiation and growth of fatigue cracks from the intergranular creep cracks. The casting defects do not play any important role as regards the lifetime under investigated loading conditions.",
  address="Elsevier Ltd",
  chapter="152036",
  doi="10.1016/j.prostr.2017.11.059",
  howpublished="print",
  institution="Elsevier Ltd",
  number="1",
  volume="7",
  year="2017",
  month="december",
  pages="44--49",
  publisher="Elsevier Ltd",
  type="journal article - other"
}