Y.-D. Song's research while affiliated with Nanjing University of Aeronautics & Astronautics and other places

... Hu et al. [9] suggested that the low cycle fatigue (LCF) properties of FGH96 superalloy were sensitive to surface defects, such as surface scratches and surface inclusion. Jiang et al. [11,12] discussed the mechanism of fatigue crack growth controlled by microstructural features in the review, indicating that the appliance of X-ray computed tomography, diffraction contrast tomography, and in situ fatigue testing could provide a better and more intuitive assessment of fatigue crack growth behavior. The microstructure and defects of the matrix of PM greatly affect low-cycle fatigue; however, surface integrity is also critical since fatigue cracks are initiated on the surface [13]. ...

... As a result, the aerospace industry desperately needs alloy materials that can withstand high temperatures [2]. Powder superalloys are well suited for such critical components [3][4][5] and fourth-generation powder superalloy turbine disks are in development to withstand temperatures reaching 815 • C. As temperature and performance requirements rise, new design concepts, compositions and processes must be developed for a new generation of powder superalloy turbine disks [6][7][8] and to mitigate the length and high cost of new material development. High entropy alloys (HEAs) with novel designs are an increasing focus of research, and related concepts are gaining in popularity. ...

... Globally, the tool manufacturers applied ultra-hard thin film coating to provide better cutting performances like low friction coefficient and thermal conductivity, higher resistance to abrasive wear, prevent destructive high temperature effects in cutting zone and chemical inertness. The most commonly used monolayer coated carbide tools with several deposition material films include TiC, 11,12 TiN, [13][14][15][16] TiCN, 17,18 TiAlN, [19][20][21][22] TiAlxN, 23 AlTiN, [24][25][26][27] specifically applied to machining of hardened steels that replaces costly ceramic and CBN tools. In the present research, as the hardness of workpiece of 57 HRC, there might be the chances of more catastrophic failure for ceramic tools compared to coated carbides because of its high brittleness and low toughness. ...

... Such oxidation processes can promote enhanced crack initiation processes and multiple crack formation along the grain boundaries, which can give rise to crack coalescence events and therefore enhanced crack propagation rate. This is also linked to a greater extent of intergranular fracture features and results in reduced lifetime [16,17]. ...

... The damage phase-field acts to degrade the elastic energy of the material, resulting in a degradation of the stiffness matrix and a rearrangement of the internal stress field (Molnár and Gravouil, 2017). The phase field method differs from other continuum damage mechanics (CDM) approaches (Wu et al., 2018;Dapaah et al., 2020) in that the phase field method avoids damage broadening through the length scale parameter ( ) (de Borst and Verhoosel, 2016), provides an estimate of a displacement discontinuity, and utilizes an energetic formulation to allow for different types of crack evolution, rather than requiring various criteria to model damage initiation, branching, or propagation (Steinke et al., 2017). The usefulness of the phase-field method in studying damage behavior in hard biological tissues was recently demonstrated by Maghami et al. (2021a,b), particularly due to its ability to accurately predict complex damage behavior involving crack branching and multiple damage fronts. ...

... When the angle was large, the inhibitory effect was intense and could even make the crack propagation stop. This is consistent with the conclusion reached by Zhu [11] and Wu [15] when studying the fatigue crack growth behavior of nickel-based alloy GH4169. ...

... Based on the above analysis, many studies are conducted in-depth on the failure rate of materials, but the most only focuses on constant cyclic loading. In fact, many components operate under random and complex loads [22,23], so the uncertainty of the load should be considered during the modeling process of failure rate. In this paper, the mapping relationship between external cyclic stress and fatigue life is studied, and the conversion mechanism between the probability distribution of cyclic stress and the probability distribution of Ti-6246 alloy fatigue life is revealed. ...

... Two traditional critical plane approaches for multiaxial fatigue analysis presented in this section, and the recent processes on multiaxial notch fatigue analysis are introduced. According to the multiaxial fatigue test results and models established for notched components, fatigue initiation usually starts from a specific plane [85][86][87], in which one or more characteristic parameters play a dominate role. ...

... Notches in real components play a decisive role in the fatigue process. There are numerous approaches to evaluate notched structures, e.g., support factor concepts, respectively, stress gradient-based approaches [7,25], the Theory of Critical Distance (TCD) by Taylor [26], approaches based on the strain energy density [27], energy field intensity approaches [28,29], concepts based on the weakest-link theory [30,31], probabilistic models [32,33], among others. Spaggiari et al. [34] present a comparison between the TCD and the classical stress gradient based approach for the fatigue assessment of notched components and point out the advantages and disadvantages of the approaches. ...

... Thus, validity verification research works have been subsequently performed. Specifically, in their following research, 87 65,66,89,90 initially analysed the fatigue strength of notch components on the basis of a newly defined critical plane-based multiaxial fatigue model. However, they only considered stress-strain data collected from notch tip and overlooked the impact of notch effect, thus the predicted results overall tend to be conservative. ...