摘要
考察了国产 18MnHP钢材预先塑性应变对疲劳裂纹扩展的影响 ,研究了国产 18MnHP钢材和国产LY11—CZ铝合金单峰超载所引起的疲劳裂纹扩展的延迟阻碍现象。通过实验结果分析可知 :①单调预拉塑性应变对疲劳裂纹扩展速率无影响 ;②预先拉压循环塑性应变导致对疲劳裂纹扩展速率的提高 ,是由循环塑性应变造成损伤所引起的 ;③超载后裂尖前沿材料的应变硬化不是导致延迟阻碍现象产生的原因 ,而宜用裂纹闭合效应来解释延迟阻碍现象。
The influence of pre-plastic strain on the fatigue crack growth in 18MnHP steel and the retardation phenomenon induced by occasional overloading in 18MnHP steel and LY11-CZ aluminium are studied experimentally.It is shown that, under the condition of the present experiments:①the fatigue crack growth rate is not effected by the pre-plastic tensile strain; ②the crack growth is accelerated by the pre-cyclic alternative plasic strain and this may be referred to the damages accumulated due to the pre-cyclic strain;③the retardation phenomenon following the occasional overloading can not be explained as a result of strain hardening of the material in front of the crack tip and the author intends to refer the retardation phenomenon to the closure effect of the fatigue crack.
出处
《株洲工学院学报》
2002年第4期128-130,共3页
Journal of Zhuzhou Institute of Technology
