Fatigue Crack Propagation in Haynes 230: A Comparison between Single and Polycrystal Crack Closure Levels

Abstract:

An experimental campaign was developed to evaluate fatigue crack growth in Haynes 230. The effects of plasticity induced crack closure were investigated with Digital Image Correlation. In particular, crack opening levels were measured with the digital extensometer technique, which allowed the evaluation of crack flanks relative displacements. Experimental results were compared with a reference da/dn – ΔK_eff curve and with the data of a previous study, which analyzed single crystal propagation. It was found that the adoption of crack closure local measurements provided an accurate estimation of crack propagation driving forces, since all the experimental points from single crystals and polycrystals collapse onto the da/dn – ΔK_eff curve.

• Periodical: Solid State Phenomena (Volume 258)
• Pages: 243-248
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.258.243
• Online since: December 2016
• Authors: Stefano Beretta*, Stefano Foletti, Silvio Rabbolini, Huseyin Sehitoglu
• Keywords: Crack Closure, Crack Propagation, Fatigue, Stress Intensity Factor Range, Superalloy

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