含ZrAl-Cu-Mg合金的微观组织与疲劳行为

Microstructures and fatigue behavior of Al-Cu-Mg alloy containing Zr

采用常规力学性能和疲劳性能测试、扫描电镜以及透射电镜观察等研究T3和T4热处理制度对含ZrAl-Cu-Mg合金组织和疲劳性能的影响。结果表明:该合金在T3状态下具有更好的综合性能。预变形引入高密度位错导致合金屈服强度显著提高,而伸长率降低不多。当应力比为0.5时,T3状态合金的S-N曲线位于T4状态之上,经106循环周次后,T3状态合金的疲劳强度比T4状态的高10MPa。在应力强度因子幅度△K相等的条件下,T3状态合金的疲劳裂纹扩展速率比T4状态的略慢。

The effects of T3 and T4 heat treatments on the microstructures and fatigue properties of AI-Cu-Mg alloy containing Zr were studied by tensile and fatigue test, SEM and TEM observations. The results show that the alloy has better combined properties at T3 condition. The high density dislocation introduced by pre-deformation significantly increases yield strength and slightly decreases elongation of the alloy. When the stress ratio is 0.5, with the same level cycles, the fatigue strength at T3 condition is higher than that at T4 condition, such as the fatigue strength （σmax） at 106 cycles is higher 10 MPa than that at T4 condition. Under the same level of stress intensity factor range AK, the fatigue crack propagation rate （da/dN） at T3 condition is slower than that at T4 condition.