金属材料低温疲劳性能的预测方法

本文总结了作者近来研究金属低温疲劳取得的进展,主要内容包括:疲劳极限的热激活模型、应变疲劳公式、疲劳始裂寿命和裂纹扩展速率的定量预测方法、疲劳裂纹扩展机制脆转模型。当室温下的疲劳极限和门槛植ΔK_(th)确定后,应用本文的方法可根据拉伸性能定量预测材料在低温下的疲劳极限、应变疲劳寿命、疲劳始裂寿命和裂纹扩展速率,并且不需要低温疲劳试验和经验修正。

MODELING OF FATIGUE BEHAVIOUR OF METALS AT LOW TEMPERATURES

The models and methods recently developed by the authors to predict fatiguebehaviour of metals at low temperatures are summarized in this paper.They include thermalactivation model of endurance limit,fatigue formula under cyclic strain,expressions of fatiguecrack intiation(FCI)life and fatigue crack growth(FCG)rate,ductile-brittle transition modelof FCG mechanism.By means of these models and methods,the fatigue properties at low tem-peratures,such as FCI life and FCG rate,can be quantitatively predicted from tensile propertiesof materials without additional low temperature fatigue test and without any empirical modifi-cation,as the endurance limit and FCG threshold at room temperature are known.