Super long fatigue properties of Al-Si-Cu die casting aluminum alloys were studied in ambient air and vacuum environment. The effects of vacuum were discussed through a comparison of S-N properties and delicate fractography. The accuracy of estimated fatigue limit by means of conventional São Paulodic;area parameters model were also discussed. Major findings in present study are as follows. (1) The fatigue lives obtained in vacuum are always longer than that obtained in ambient air. (2) The data obtained in vacuum for present study and reference data of fracture originated internal defect with ultrasonic fatigue tests are lies approximately same region on the S-N diagram. Also, it is noted that the interior fracture origin and fish-eye appeared in over 10 7 cycles regime can be reproduced in vacuum environment under 10 7 regime. (3) In case of specimen broken in vacuum environment, a little nano-particles layer observed at localized area in the bottom of artificial small hole. (4) In case of fatigue fracture originated from surface defects, fatigue limit was well estimated by means of São Paulodic;area parameter model with Noguchi's correction method. Although in case of data obtained in the vacuum, there are some deviation from the estimate target. © 2010 Published by Elsevier Ltd.
Ueno, A., Miyakawa, S., Yamada, K., & Sugiyama, T. (2010). Fatigue behavior of die casting aluminum alloys in air and vacuum. In Procedia Engineering (Vol. 2, pp. 1937–1943). https://doi.org/10.1016/j.proeng.2010.03.208