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 the out-of-phase thermo-mechanical fatigue (OPTMF)lifetime of the A356.0 cast aluminum alloy is investigated. Studied parameters include themaximum temperature, the dwell time, and the thermo-mechanical loading factor. OP-TMF tests areconducted 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 the mechanical strain to the thermal strain, is considered between 75 to 150%. The dwell time (orthe holding time) changes between 5 to 180 sec. at the maximum temperature. Fracture surfaces of specimens are studied using the scanning electron microscopy (SEM). These SEM images reveal that the A356.0 alloy has a ductile behavior. The cyclic softening phenomenon is also observed duringstress-strain hysteresis loops. TMF test results demonstrate that the dwell time bears no significant effect upon the lifetime. However, large influences for the maximum temperature and the thermomechanical loading factor are depicted in the lifetime of the A356.0 alloy

Keywords:

Thermo-mechanical Fatigue , A356.0 Aluminum Alloy , Dwell Time , Maximum Temperature , Cyclic Softening