GH36合金持久缺口敏感性与蠕变和疲劳及其交互作用下的裂纹扩展速率

Influence of Stress Rupture Notch Sensitivity on Crack Growth Rates at Creep, Fatigue and Creep/Fatigue Interaction Conditions in GH36 Superalloys

摘要: 研究了GH36合金持久缺口敏感性对裂纹扩展速率的影响。结果表明:通过软化的热处理制度来改善材料的持久塑性达到消除持久缺口敏感性的目的,对在蠕变或以蠕变为主的应力条件下延缓裂纹的扩展具有重要意义;而在低周疲劳或以疲劳为主的应力条件下,裂纹扩展速率对强度敏感,而与材料是否存在持久缺口敏感性无关;提高强度可显著提高材料的抗低周疲劳裂纹扩展能力。为使材料在蠕变、疲劳以及蠕变疲劳交互作用下都只有高的抗裂纹扩展能力,应对材料进行强韧化。

Abstract: The influence of stress rupture notch sensitivity on crack growth rates have been investigated in GH36 iron-base superalloy discs.Stress rupture ductility improvement can eleminate stress rupture notch sensitivity and decrease the crack growth rates under creep condition or where creep is the dominant failure mode. But under fatigue condition, the crack growth raets are sensitive to material strength and independent of stress rupture notch sensitivity.Material strength improvement can significantly increase the resistance to low cycle fatigue crack growth.In order to improve the resistance to crack growth under creep, fatigue and creep/fatigue interacton, materials should be improved in both strength and ductility.