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为了确定稀土元素Sc对T6态铸造Al-9.0%Si-4.0%Cu-0.4%Mg合金(质量分数)的低周疲劳行为的影响规律,研究了T6态铸造Al-9.0%Si-4.0%Cu-0.4%Mg合金和Al-9.0%Si-4.0%Cu-0.4%Mg-0.3%Sc合金的低周疲劳行为.结果表明,在低的外加总应变幅下,Al-9.0%Si-4.0%Cu-0.4%Mg合金在整个疲劳变形期间均表现为循环应变硬化,Al-9.0%Si-4.0%Cu-0.4%Mg-0.3%Sc合金在疲劳变形初期表现为循环应变硬化,在疲劳变形后期则表现为循环稳定;当外加总应变幅较高时,Al-9.0%Si-4.0%Cu-0.4%Mg(-0.3%Sc)合金均呈现循环应变硬化.Sc的加入可以有效地提高T6态Al-9.0%Si-4.0%Cu-0.4%Mg合金的循环变形抗力和低周疲劳寿命.在较低的外加总应变幅下,T6态Al-9.0%Si-4.0%Cu-0.4%Mg(-0.3%Sc)合金的循环变形机制为平面滑移,当外加总应变幅较高时则为波状滑移机制.
In order to determine the effect of rare-earth element Sc on the low-cycle fatigue behavior of Al-9.0% Si-4.0% Cu-0.4% Mg alloy cast in T6 state, Low-cycle fatigue behavior of Al-9.0% Si-4.0% Cu-0.4% Mg-0.3% Sc alloy was investigated.The results show that Al-9.0% Si-4.0% Cu-0.4% Mg alloy showed cyclic strain hardening during the whole fatigue deformation. The Al-9.0% Si-4.0% Cu-0.4% Mg-0.3% Sc alloy exhibited cyclic strain hardening during the initial stage of fatigue deformation. The cycle stability is shown when the total applied strain is high, and the strain hardening of Al-9.0% Si-4.0% Cu-0.4% Mg (-0.3% Sc) alloy exhibits cyclic strain hardening.Addition of Sc can effectively increase the T6 state Al-9.0% Si-4.0% Cu-0.4% Mg alloy.The results show that the T6 Al-9.0% Si-4.0% Cu-0.4% Mg -0.3% Sc) alloy is a plane slip, and the wavy slip mechanism when the total applied strain is higher.