温度和加载速率对LY12CZ薄板材料断裂韧性的影响

Effect of different temperature and strain rates on thin plate aluminum alloy LY12CZ

以飞机结构常用的铝合金材料LY12CZ为研究对象 ,研究了温度、加载速率对平面应力弹塑性I型裂纹起裂和扩展的影响。通过实验研究和数值分析 ,得到了以下四点结论 ,(1)用断裂丝片测量裂纹稳定扩展段的长度是可行的 ;(2 )静态载荷作用下的起裂韧性变化不大 ,但随温度的升高 ,材料在裂纹扩展过程中断裂韧性会降低 ;(3)低速冲击载荷作用下的弹塑性动态起裂韧性比静态值要小 40 % ;(4 )与增量路径无关积分的计算结果进行比较 ,说明在本研究情况下 。

In this paper, the effects of three kinds of temperature and two kinds of strain rates on the LY12CZ plate are studied. From the experimental study and the numerical analysis, four conclusions can be made. Firstly, the method to determine the stable crack growth in experiment is workable. Secondly, the initiation fracture toughness is unchanged under different temperature, while for the crack propagating process, the fracture toughness decrease as the environment temperature increase. Thirdly, the dynamic initiation fracture toughness is 40% lower than that of the quasi-static condition. Fourthly, by comparing with the incremental path-independent integral, the dynamic J integral can be used widely.