Effect of microstructural constituents on the thermal fatigue life of A319 aluminum alloy

In this investigation, the effect of microstructural constituents on thermal fatigue resistance of A319 aluminum casting alloy was studied. For this purpose, both thermo-mechanical fatigue and thermal-shock fatigue experiments were performed in thermal cycling range between 40 and 250 °C. Following the results, samples with finer SDAS, lower porosity volume fraction and lower brittle intermetallic contents, as well as higher Si modification showed better thermal fatigue resistance. Moreover, T6 and T7 heat treatments appeared to be highly beneficial for thermal fatigue performance. According to the fractography analysis, porosities and coarse intermetallic phases were determined as the most prime locations for crack propagation.