周期过载对LY12CZ铝合金腐蚀疲劳裂纹扩展的影响

 对ＬＹ１２ＣＺ铝合金在周期过载条件下腐蚀疲劳裂纹扩展特性进行了试验研究。结果表明，周期过载迟滞效应取决于过载比和过载周期。当每一过载周期内裂纹扩展量小于由过载引起的塑性区尺寸时，可用等幅腐蚀疲劳裂纹扩展公式很好地拟合周期过载腐蚀疲劳裂纹扩展速率实验结果，从而周期过载迟滞裂纹扩展速率可通过在等幅腐蚀疲劳裂纹扩展公式中引入迟滞系数而获得。高－低加载顺序对腐蚀疲劳裂纹扩展的影响主要出现在近门槛区。

EFFECTS OF PERIODIC OVERLOADS ON CORROSION FATIGUE CRACK PROPAGATION IN LY12CZ ALUMINUM ALLOY

An experimental investigation on corrosion fatigue crack propagation (CFCP) under periodic overloads in LY12CZ oluminum alloy is carried out.The retardation under periodic overloads depends on overload ratios and overload periods.When the crack propagation in each overload period is less than the plastic zone caused by overloads,the CFCP rates under periodic overloads follow closely the constant amplitude CFCP behavior so that they can be modeled as a pseudo-constant amplitude CFCP behavior.In the high-low loading sequence,the retardation of CFCPmainly takes place near to the threshold range.