MSE 2016 - Full Program

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Highlight Lecture

Effect of microstructure on fatigue behavior of advanced high strength steels produced by quenching and partitioning and the role of retained austenite

Tuesday (27.09.2016)
11:15 - 11:30
Part of:

Despite the significant body of research on mechanical properties of quenched and partitioned (Q&P) steels, their fatigue behavior has been scarcely investigated. This work focuses on the effect of microstructure on high cycle fatigue of Q&P steels and microstructural evolution during cyclic loading. It is demonstrated that increased content of retained austenite (RA) improves fatigue limit of Q&P steels that is related to delay of crack propagation due to austenite-martensite phase transformation. Increasing stress amplitude promotes austenite-martensite phase transformation during cycling loading. It is shown that size and crystallographic orientation of RA are the main factors determining its stability, whereas its shape and spatial distribution do not seem to affect it significantly. Fatigue crack initiation during fatigue testing with high stress amplitudes occurs by intergranular cracking, whereas transgranular cracking controls fatigue crack initiation during cycling loading with lower stress amplitudes. Transgranular crack propagation dominates in the second stage of fatigue at all stress amplitudes. The final stage of fatigue is also not affected by the stress amplitude. It is suggested that fatigue life of Q&P steels can be enhanced via improvement of strength of grain/interphase boundaries. Fatigue properties of Q&P steels will be compared with those of other advanced high-strength steels (AHSS).

Additional Authors:
  • Dr. Pablo Rodriguez-Calvillo
    Fundació CTM Centre Tecnològic, Universitat Politècnica de Catalunya
  • Dr. Antoni Lara
    Fundació CTM Centre Tecnològic
  • Dr. Jon Molina-Aldareguia
    IMDEA Materials Institute
  • Prof. Dr. Roumen Petrov
    Ghent University, Delft University of Technology
  • Dr. Dorien De Knijf
    Ghent University
  • Dr. Ilchat Sabirov
    IMDEA Materials Institute