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The thresholds of short fatigue cracks for aluminum-lithium alloys 2090 and 2090+Ce are quantitatively evaluated. The essential reason resulting in stronger short crack effect has been ascertained. Influence of cerium on the threshold of short fatigue cracks for aluminum-lithium alloy 2090 was investigated. The results show that, by adding Ce into this alloy,△Ki and △KClth are increased. The influence mechanism of Ce on the threshold of short fatigue crack for alloy 2090 was explored from the bound energy, T1 phase, the energy of anti-phase boundary the energy of super-lattice intrinsic stacking fault and the electron bonds. By adding Ce into alloy 2090, the bound energy of Cu atom in this alloy is increased; the effect of thinning and dispersing T1 phase is obtained; the effect of increasing the energy of anti-phase boundary and decreasing the energy of super-lattice intrinsic stacking fault for δ’ phase can be achieved.
The thresholds of short fatigue cracks for aluminum-lithium alloys 2090 and 2090 + Ce are quantitatively evaluated. The essential reason resulting in stronger short crack effect has been ascertained. Influence of cerium on the threshold of short fatigue cracks for aluminum-lithium alloy 2090 was investigated. The results show that, by adding Ce into this alloy, △ Ki and △ KClth are increased. The influence mechanism of Ce on the threshold of short fatigue crack for alloy 2090 was explored from the bound energy, T1 phase, the energy of anti-phase boundary the energy of super-lattice intrinsic stacking fault and the electron bonds. By adding Ce into alloy 2090, the bound energy of Cu atom in this alloy is increased; the effect of thinning and dispersing T1 phase is obtained; the effect of increasing the energy of anti-phase boundary and decreasing the energy of super-lattice intrinsic stacking fault for δ ’phase can be achieved.