PSI - Issue 2_B

M. Meischel et al. / Procedia Structural Integrity 2 (2016) 1077–1084 Author name / Structural Integrity Procedia 00 (2016) 000–000

1084

8

In summary, the following conclusions may be drawn: A corrosive attack of the NaCl solution takes place at the specimen surfaces which causes surface crack initiation and no interior cracks. One or two surface cracks were also formed perpendicular to the main fracture surface. It is assumed that, NaCl solution penetrating along grain boundaries is responsible for this. The fracture surfaces are rougher, more brittle and show deeper and secondary cracks to a greater extent. These secondary cracks are probably responsible for the observed fatigue-crack growth retardation. Acknowledgements This work is based on research funded by US Naval Air System Command under guidance of Dr. Nam Phan. Special thanks go to Dr. Bernd Schönbauer for providing the corrosion chamber and Dr. Michael Fitzka for experimental support with the equipment. Arcari, A., Apetre, N., Dowling, N., Meischel, M., Stanzl-Tschegg, S., Iyyer, N., Phan, N. 2015. Variable amplitude fatigue life in VHCF and probabilistic life predictions. Procedia Engineering 114, 574-582. Fitzka, M., Mayer, H., Schuller, R., Stanzl-Tschegg, S. E., Przeorski, T., Krug, P. 2014. Variable amplitude loading of spray-formed hypereutectic aluminium silicon alloy DISPAL® S232 in the VHCF regime. Fatigue & Fracture of Engineering Materials & Structures 37(9). 945-957. Mayer, H. 1999. Fatigue crack growth and threshold measurements at very high frequencies. International Materials Reviews 44(1). 1-34. Mayer, H., Fitzka, M., Schuller, R. 2013. Constant and variable amplitude ultrasonic fatigue of 2024-T351 aluminium alloy at different load ratios. Ultrasonics 53(8). 1425-1432. Mayer, H., Fitzka, M., Schuller, R. 2014. Variable amplitude loading of Al 2024-T351 at different load ratios using ultrasonic equipment. International Journal of Fatigue 60. 34-42. Mayer, H., Papakyriacou, M., Stanzl-Tschegg, S., Tschegg, E., Zettl, B., Lipowsky, H., Rösch, R., Stich, A. 1999. Corrosion fatigue of cast aluminium- and cast magnesium alloys. Materials and Corrosion/Werkstoffe und Korrosion 50(2). 81-89. Meischel, M., Stanzl-Tschegg, S. E., Arcari, A., Iyyer, N., Apetre, N., Phan, N. 2015. Constant and variable-amplitude loading of aluminum alloy 7075 in the VHCF regime. Procedia Engineering 101. 501-508. Sarrazin-Baudoux, C., Stanzl-Tschegg, S. E., Schönbauer, B. M., Petit, J. 2016. Ultra slow fatigue crack propagation in metallic alloys. ICMFM18. Schönbauer, B. M., Stanzl-Tschegg, S. E., Perlega, A., Salzman, R. N., Rieger, N. F., Zhou, S., Turnbull, A. Gandy, D. 2014. Fatigue life estimation of pitted 12% Cr steam turbine blade steel in different environments and at different stress ratios. International Journal of Fatigue 65. 33-43. Stanzl, S. 1981. A new experimental method for measuring life time and crack-growth of materials under multistage and random loadings. Ultrasonics 19(6). 269-272. Stanzl-Tschegg, S. E., Meischel, M., Arcari, A., Iyyer, N., Apetre, N., Phan, N. 2015. Combined cycle fatigue of 7075 aluminum alloy – Fracture surface characterization and short crack propagation. International Journal of Fatigue. doi: 10.1016/j.ijfatigue.2015.10.022. References