Fatigue Life Assessment of A356 Aluminum Alloy used for Engine Cylinder Head

Abstract The main aim of this study is assessing fatigue resistance of casting A356 alloy for the manufacture of engine cylinder heads at high temperatures. Testing for isothermal and in-phase thermo-mechanical fatigue was conducted at 120ºC and 280ºC and from 120ºC to 280ºC, respectively. The fatigue crack growth rate was estimated, employing different waveforms under displacement and load control. The objective to perform the relaxation tests at temperatures ranging from 75oC to 280oC was to obtain further information for modeling. The results showed that casting defects and heterogeneities of the material in conjunction with long testing times at high temperatures and under different loading waveforms are critical factors in determining fatigue performance. These research findings will provide parameters for simulating the evolution of mechanical properties of the material under investigation under cyclic loadings at high temperatures, whether isothermal or thermo-mechanical, to later validate the crack propagation model proposed by Pommier and Risbet (2005).