摘要
基于裂纹尖端钝化理论及尖切口根部断裂准则,以裂纹尖端临界钝化半径ρc为两种模型的物理关联点,提出了裂纹尖端微试棒材料元受载方向的变形能力即延伸率δ与ρc直接相关的假设,进而给出了高塑性金属材料断裂韧性预测的δ模型。分析表明断裂韧性KIc与材料的弹性模量和延伸率相关,而对于同一种材料,则断裂韧性KIc仅与延伸率相关。2124铝合金在不同热处理状态和不同取向上的试验结果验证了上述δ模型的正确性。给出了2124铝合金断裂韧性KIc定量估算的线性表达式,且预测结果与试验结果符合性较好。
On the basis of the crack tip blunting theory and fracture criterion of notched elements,when the blunted crack tip radius ρ reaches the critical blunted crack tip radius value ρc,the cracked element can be considered as notched element. A simple model for predicting plane-strain fracture toughness KIcfor ductile materials was obtained on the assumption that there was a direct relationship between ρcand the deformation capacity of the hypothetical material element located ahead of the notch tip,i.e.,elongation δ. The analysis on the model show that the value of KIcis apparently related to the elasticity modulus and the elongation. Furthermore,for a given material KIcis associated exclusively with δ. The mechanical properties test,including smooth tensile test and KIctest for 2124 aluminum alloy were carried out with specimens with different heat treatment state and different orientation directions. The experimental results show a significant linear correlation between KIcand δ,which verify the correctness of the present model.
出处
《机械科学与技术》
CSCD
北大核心
2015年第9期1451-1454,共4页
Mechanical Science and Technology for Aerospace Engineering
关键词
铝合金
延伸率
钝化
裂纹尖端临界钝化半径
弹性模量
估算
aluminum alloy
blunting
critical blunted crack tip radius
deformation
ductility
elasticity modulus
elongation
