Low cycle thermal fatigue and microstructural change of AC2B-T6 aluminum alloy

Abstract

Low cycle thermal fatigue tests were conducted using an aluminum alloy AC2B-T6, which is widely used in diesel engines, especially, in cylinder heads. Specimens made of the AC2B-T6 alloy were subjected to thermal fatigue with thermo-mechanical loadings over several temperature ranges, symmetric and asymmetric strain amplitudes, and cycle periods. These test conditions are chosen considering realistic running conditions of diesel engines. A method to predict time to fatigue failure under the test conditions is proposed. The specimens were also observed by transmission electron microscope (TEM) to clarify the effects of temperature, strain amplitude, and cycle period on microstructural changes such as precipitates. Finally, the relationship between the microstructural changes and the low cycle thermal fatigue is discussed

Heat treatment effect on thermo-mechanical fatigue and low cycle fatigue behaviors of A356.0 aluminum alloy

“…As an example, thermal barrier coatings lead to lower thermal stresses due to lower temperature gradient. Another example is to strengthen the material with a typical heat treatment process [1][2][3].…”

Effects of strain rate and mean strain on cyclic behavior of aluminum alloys under isothermal and thermo-mechanical fatigue loadings

“…No significant difference in the fatigue life was observed in low cycle fatigue regime due to the mean stress relaxation by cyclic plasticity. Sasaki and Takahashi [7] conducted low cycle thermal fatigue tests on an aluminum alloy under symmetric and asymmetric strain amplitudes. Their results showed that the stresses at the maximum and minimum strains of three mean strain tests of À0.15%, 0.15%, and À1.55% were almost the same values, while those of zero mean strain test were a little smaller than the others.…”

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

“…The measured value of the stress relaxation is about 15 to 20 MPa for all dwell times (shown in Figure 16). Sasaki and Takahashi [36] also reported about 20 MPa stress relaxation for the AC2B-T6 aluminum alloy under 5 to 20 min of the dwell time. According to their studies, they depicted that the stress relaxation started at about 220°C which is about 56% of the melting point of aluminum alloys.…”