Modeling and Analysis of Effect of Thermal Exposure on Fatigue Crack Growth of Al-Cu-Mg Alloys with Low Cu/Mg Ratio

Effect of thermal exposure on FCG of Al-Cu-Mg alloys with low Cu/Mg ratio in artificial and natural ageing conditions were modeled and analyzed. Three FCG rate models, namely Collipriest, Priddle, and Modified Forman model were examined to research the effect of thermal exposure on FCG of Al-Cu-Mg alloys with low Cu/Mg ratio in artificial and natural ageing conditions. The results showed that Priddle model provided the best fit. Priddle model was used to fit FCG data of (a) 170°C/30min ageing; (b)170°C/30min ageing +100°C/2000h exposure; (c)T351 ageing+100°C/2000h exposure; (d)T351 ageing. The fitted results indicated that the FCP resistance can be increased by slight artificial aging, and artificial aging can delay the degradation of the fatigue properties