Georgia Institute of Technology, Atlanta, GA, USA, and Washington State University, Pullman, WA, USA
Philos Trans A Math Phys Eng Sci. 2015 Mar 28;373(2038). doi: 10.1098/rsta.2014.0128.
Nickel-base superalloys are primarily used as components in jet engines and land-based turbines. While compositionally complex, they are microstructurally simple, consisting of small (50-1000 nm diameter), ordered, coherent Ni(3)(Al,Ti)-type L1(2) or Ni(3)Nb-type DO(22) precipitates (called γ(') and γ(''), respectively) embedded in an FCC substitutional solid solution consisting primarily of Ni and other elements which confer desired properties depending upon the application. The grain size may vary from as small as 2 μm for powder metallurgy alloys used in discs to single crystals the actual size of the component for turbine blades. The fatigue behaviour depends upon the microstructure, deformation mode, environment and cycle time. In many cases, it can be controlled or modified through small changes in composition which may dramatically change the mechanism of damage accumulation and the fatigue life. In this paper, the fundamental microstructural, compositional, environmental and deformation mode factors which affect fatigue behaviour are critically reviewed. Connections are made across a range of studies to provide more insight. Modern approaches are pointed out in which the wealth of available microstructural, deformation and damage information is used for computerized life prediction. The paper ends with a discussion of the very important and highly practical subject of thermo-mechanical fatigue (TMF). It is shown that physics-based modelling leads to significantly improved life prediction. Suggestions are made for moving forward on the critical subject of TMF life prediction in notched components.
镍基高温合金主要用作喷气发动机和陆基涡轮机的部件。虽然成分复杂，但它们的微观结构却很简单，由小（50-1000nm 直径）、有序、共格的 Ni(3)(Al,Ti)-型 L1(2)或 Ni(3)Nb-型 DO(22)沉淀物（分别称为 γ(')和 γ(')）组成，这些沉淀物嵌入由 Ni 和其他元素组成的 FCC 置换固溶体中，具体元素取决于应用。晶粒尺寸从用于盘的粉末冶金合金的 2μm 到涡轮叶片的实际部件的单晶尺寸不等。疲劳行为取决于微观结构、变形模式、环境和循环时间。在许多情况下，可以通过成分的微小变化来控制或改变疲劳行为，这可能会极大地改变损伤累积和疲劳寿命的机制。本文批判性地回顾了影响疲劳行为的基本微观结构、成分、环境和变形模式因素。通过一系列研究建立了联系，以提供更深入的了解。指出了现代方法，其中利用了大量可用的微观结构、变形和损伤信息，用于计算机化寿命预测。本文最后讨论了非常重要和非常实际的热机械疲劳（TMF）主题。结果表明，基于物理的建模可显著提高寿命预测的准确性。对缺口部件 TMF 寿命预测这一关键主题提出了前进的建议。
