The Effect of Various Parameters on Out-of-phase Thermo-mechanical Fatigue Lifetime of A356.0 Cast Aluminum Alloy

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.