Measurement of Strain Localization Resulting from Monotonic and Cyclic Loading at 650°C in Nickel Base Superalloys

Jean-Charles Stinville (1) , Mclean P. Echlin (1) , Patrick G. Callahan (1) , Victoria M. Miller (1, 2) , Damien Texier (3) , Florent Bridier (4) , Philippe Bocher (3) , Tresa M. Pollock (1)

1 UC Santa Barbara - University of California [Santa Barbara]
2 NC State - North Carolina State University [Raleigh]
3 ETS - Ecole de Technologie Supérieure [Montréal]
4 DCNS - DCNS Group

A methodology is presented for the use of the oxide scale that develops in polycrystalline Ni-base super-alloys at service temperature, as a speckle pattern for μm-scale resolution strain measurements. Quantitative assessment of the heterogeneous strain field at the grain scale is performed by high-resolution SEM digital image correlation under monotonic and cyclic loading in polycrystalline Ni-base superalloys up to 650 • C. In the René 88DT superalloy, strain localization is observed near twin boundaries during low cycle fatigue (LCF) at intermediate temperatures, correlating with activation of {111}}110 and {111}}112 slip systems. A strong correlation between the microstruc-tural configuration that promotes strain localization during monotonic loading and crack initiation at 650 • C in low cycle fatigue was observed.

Mots clés: Strain; High temperature fatigue; Rene88DT; localization; Polycrystalline superalloy; High resolution digital image correlation ·

Domaines: Mécanique des matériaux [physics.class-ph]; Mécanique des matériaux [physics.class-ph]

Jean-Charles Stinville, Mclean P. Echlin, Patrick G. Callahan, Victoria M. Miller, Damien Texier, et al.. Measurement of Strain Localization Resulting from Monotonic and Cyclic Loading at 650°C in Nickel Base Superalloys. Experimental Mechanics, 2017, 57 (8), pp.1289-1309. ⟨10.1007/s11340-017-0286-y⟩. ⟨hal-01662651⟩