Microstructural statistics for fatigue crack initiation in polycrystalline nickel-base superalloys

Jean-Charles Stinville (1) , William C. Lenthe (1) , Mclean P. Echlin (1) , Patrick G. Callahan (1) , Damien Texier (2) , Tresa M. Pollock

1 UC Santa Barbara - University of California [Santa Barbara]
2 ETS - Ecole de Technologie Supérieure [Montréal]

In advanced engineering alloys where inclusions and pores are minimized during processing, the initiation of cracks due to cyclic loading shifts to intrinsic microstructural features. Criteria for the identification of crack initiation sites, defined using elastic-plastic loading parameters and twin boundary length, have been developed and applied to experimental datasets following cyclic loading. The criteria successfully quantify the incidence of experimentally observed cracks. Statistical microstructural volume elements are defined using a convergence approach for two nickel-base superalloys, IN100 and René 88DT. The material element that captures the fatigue crack-initiating features in René 88DT is smaller than IN100 due to a combination of smaller grain size and higher twin density .

Mots clés: Fatigue initiation volume element; Polycrystalline superalloys, Strain localization, Low; cycle fatigue, Fatigue initiation, High resolution; digital image correlation

Domaines: Mécanique des matériaux [physics.class-ph]; Micro et nanotechnologies/Microélectronique; Mécanique des matériaux [physics.class-ph]; Matériaux

Jean-Charles Stinville, William C. Lenthe, Mclean P. Echlin, Patrick G. Callahan, Damien Texier, et al.. Microstructural statistics for fatigue crack initiation in polycrystalline nickel-base superalloys. International Journal of Fracture, 2017, 208 (1-2), pp.221 - 240. ⟨10.1007/s10704-017-0241-z⟩. ⟨hal-01662675⟩