Material improvement by artificial aging for aluminum alloy of cylinder head (influence on inelastic behavior and thermal fatigue life)

Past efforts for aluminum alloys used for engines were focused on chemical compositions rather than heat treatment conditions of the aluminum alloys. Then, there are a few studies on optimizations of the heat treatment conditions. This paper treats artificial aging effects on two aluminum alloys such as AC 4 C and AC 2 B used for cylinder heads of engines. The aluminum alloys are subjected to additional heat treatments during several time periods after T 6 heat treatments. The effects of the aging time on the mechanical behaviors such as pure tension, cyclic loading, and thermo-mechanical fatigue failure are observed by a series of tests. The microstructural observation is also carried out by TEM to clarify the effects of microstructural change of the aluminum alloys on the mechanical behaviors.