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本文旨在研究夹杂-细晶粒区-鱼眼诱发疲劳失效的超长寿命预测模型.基于Cr-Ni-W合金钢疲劳试验结果,结合局部应力-寿命法和位错-能量法,分别构建了局部裂纹萌生寿命模型(LCIL)和考虑夹杂及细晶粒区影响的裂纹萌生寿命模型(IFCIL),并与Tanaka-Mura模型(T-M)进行了对比分析.其次,分别对细晶粒区内的小裂纹扩展行为和细晶粒区外鱼眼内的长裂纹扩展行为进行建模,最终形成了包含裂纹萌生和扩展在内的全寿命预测模型.结果表明,考虑夹杂及细晶粒区影响的裂纹萌生寿命模型(IFCIL)有较高的预测精度;对应细晶粒区的裂纹萌生寿命几乎等同于全寿命;裂纹扩展寿命仅占据全寿命很小的一部分;预测结果全部处于2倍偏差以内,即全寿命模型可有效地用于夹杂-细晶粒区-鱼眼诱发失效的超长寿命预测.
This paper aims to study the long-life prediction model of inclusion-fine grain area-fish-eye induced fatigue failure.According to the fatigue test results of Cr-Ni-W alloy steel, combined with local stress-life method and dislocation-energy method, (LCIL) and IFCIL (Incidence Cracking Lifetime) model considering the effect of inclusions and fine grain size were compared with those of Tanaka-Mura model (TM) .Secondly, And the long-lived crack propagation behavior in the fisheye outside the fine grain region were finally modeled.The life prediction model including crack initiation and propagation was finally formed.The results show that considering the influence of inclusions and fine grain size The crack initiation life model (IFCIL) has higher prediction accuracy. The crack initiation life corresponding to the fine grain region is almost the same as the full life. The crack growth life occupies only a small part of the whole life. The prediction results are all within 2 times of the deviation , That is, the full-life model can be effectively used to predict the long-lived life of inclusion-fine grain-induced fish-eye failure.