Experimental characterization of the short crack growth behavior of a ductile cast iron (DCI GJS-500) affected by intergranular embrittlement at temperatures nearby 400 ∘C. (February 2022)

• Record Type: Journal Article
• Authors: Trelles, Elena Garcia; Eckmann, Stefan; Schweizer, Christoph
• Is Part Of: International journal of fatigue. Volume 155(2022)
• Publication Date: 2022-02
• Subjects: Thermomechanical fatigue -- Intergranular embrittlement -- DCI GJS-500 -- Fatigue short crack growth -- Replica method; Materials -- Fatigue -- Periodicals; Materials -- Fatigue; Periodicals; 620.1122
• DOI: 10.1016/j.ijfatigue.2021.106573
• Languages: English
• ISSNs: 0142-1123

Abstract

Abstract: In this investigation, the fatigue and crack growth behavior of the ductile cast iron material (DCI) GJS-500 was experimentally characterized by performing isothermal low cycle fatigue (LCF) tests, out-of-phase thermomechanical fatigue (OPTMF) tests as well as low cycle fatigue tests combined with the replica testing method (LCF-R) within the temperature range RT–500 °C. The studied material exhibits an embrittlement at temperatures nearby 400 °C, leading to a significant higher fatigue crack growth rate and a reduced lifetime, when compared with RT and 500 °C. A possible explanation for the observed higher fatigue crack growth rate coupled with a significant lifetime reduction, is intergranular embrittlement. Highlights: The DCI GJS-500, a high silicon cast iron with a ferritic matrix and nodular graphite, is sensitive to intergranular embrittlement within the range 400–450 °C. Experimental fatigue short crack growth curves have been generated for the DCI GJS-500 at room temperature, 400 °C and 500 °C. Significantly higher crack growth rates are observed at 400 °C than at RT or 500 °C. Fractographic studies show an intergranular–transgranular fracture pattern at 400 °C.