Mg、Zr对GH33A合金高温疲劳以及静、动态蠕变行为的影响
Influence of Magnesium and Zirconium on High Temperature HCF, Static and Dynamic Creep Behaviours in Disc Material GH33A Superalloys
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摘要: 本文研究了含Mg、Zr与不含Mg、Zr两种GH33A合金的高温疲劳和静、动态蠕变行为。结果表明,微量元素Mg、Zr对提高疲劳性能不显著,也不能改善疲劳缺口敏感性。缺口疲劳性能取决于缺口的几何参数Kt与λ,材料的光滑疲劳极限和平均晶粒尺寸微量元素Mg、Zr的良好作用主要表现在静态蠕变条件下,充分发展和延长了蠕变第Ⅱ和第Ⅲ阶段,增加蠕变断裂延伸率,并大大提高断裂寿命。这种良好作用在恒载且迭加有疲劳交变应力的动态蠕变条件下仍然保持。Abstract: This paper investigated high temperature HCF, static and dynamic creep behaviours in GH33A superalloys with and without Mg and Zr.HCF notch sensitivity in the two alloys was analysed.Results show that a small amount of Mg and Zr can improve neither HCF properties nor fatigue notch sensitivity. Notch fatigue limit depends on smooth fatigue limit, grain size and notch geometric parameters Kt and λ (stress concentration coeffecient and stress gradient).A small amount of Mg and Zr can intensively prolong secondary creep stage and well develop tertiary creep stage, and so increase stress rupture life and stress rupture ductility significantly.The benificial effect still exists under dynamic creep condition.
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