Chair of Mechanical Engineering, University of Leoben
School of Mechanical Engineering, Sharif University of Technology
Mechanical Engineering, Sharif University of Technology
In this paper, the effect of various parameters on out-of-phase thermo-mechanical fatigue (OP-TMF) lifetime of A356.0 cast aluminum alloy is investigated. The studied parameters include maximum temperature, dwell time, and the thermo-mechanical loading factor. OP-TMF tests are conducted considering realistic running conditions of diesel engine cylinder heads. The maximum temperature varies between 200 to 275°C and the thermo-mechanical loading factor, which is the ratio of mechanical strain to thermal strain, is considered between 75 to 150%. The dwell time (or holding time) changes between 5 to 180 sec. at maximum temperature. The fracture surfaces of specimens are studied using Scanning electron microscope (SEM). These SEM images reveal that A356.0 alloy has a ductile behavior. The cyclic softening phenomenon is also observed during stress-strain hysteresis loops. The TMF tests results demonstrate that the dwell time bears no significant effect upon the lifetime. However, large influences for maximum temperature and the thermo-mechanical loading factor are depicted in the lifetime of A356.0 alloy.