Influence of Ce on the microstructure and properties of Al-Li alloy

Curves of ΔK_th vs. Δa_th and ΔK_Cl·th vs. Δa_rh for aluminum-lithium alloy 2090 have been determined and compared with those for traditional aluminum alloy 2024. The growth resistance of short fatigue cracks for aluminum-lithium alloy 2090 is quantitatively evaluated. The essential reason resulting in stronger short cracks effect has been ascertained. Influence of cerium on the growth behavior of short fatigue cracks for aluminum-lithium alloy 2090 was investigated. The results show that by adding cerium into this alloy a significant improvement in ΔK_i can be achieved and at the same time ΔK_Cl·th is increased. Consequently, the essential factor resulting in lower growth resistance of short fatigue cracks for this alloy is removed and the growth resistance of long and short fatigue cracks is increased.