Tribological studies of eutectic Aluminum-Silicon alloys used for automotive engine blocks subjected to sliding wear damage

The microstructures and wear performances of linerless engine cylinder blocks made of two eutectic Al-Si alloys with different Si morphologies were characterized after the engine tests. Overall, both the Al-11 wt. % Si alloy and the Al-12.6 wt. % Si alloy provided similar wear performance.;Block-on-ring wear tests were applied to the Al-11% Si alloy. The MW regime in air consisted of two sub-regimes: MW-1 and MW-2. The argon atmosphere produced a 10-fold reduction in wear rates and the formation of LMW regime at loads less than 10 N. The metallic tribolayers formed in the MW under argon atmosphere were uniform and stable, resulting lower wear rates than those in air. The mechanism of material removal under argon atmosphere was delimination. The SW occurring in argon was observed at a relatively low load, compared to an air atmosphere. Wear was also more sensitive to applied load in the argon atmosphere.