Effect of grain size on the near threshold fatigue crack propagation of a nickel base precipitation hardened superalloy

Effects of cryogenic temperature and grain size on fatigue-crack propagation in the medium-entropy CrCoNi alloy

“…With respect to the coarse-grained CrCoNi alloy, its fatigue crack-growth properties are comparable to nickel-based superalloys with similar large grain sizes [55][56][57]. Specifically, Inconel 718 with an intermediate grain size (22 µm) [56] has a threshold falling in between those of the fine-and coarse-grained CrCoNi, whereas large-grained (100 µm) Waspaloy is superior to the coarse-grained CrCoNi with a 25% higher fatigue threshold, although it displays a 18% higher Paris exponent [55,57].…”

“…The fatigue-crack growth performance of the CrCoNi MEA is compared to that of the CrMnFeCoNi (Cantor) high-entropy alloy [1,28] as well as other comparable structural alloysaustenitic stainless steels [46], twinning-induced plasticity (TWIP) steels [54], and nickel-based superalloys [55][56][57] -in Figure 11; further details of these alloys and their mechanical properties are summarized in Table 3. The results listed were based on fatigue-crack growth experiments performed at room temperature at an R-ratio of 0.05 -0.1.…”

“…33 Note that nano-twinning is not activated in the 68 µm structure in the near-threshold regime. stainless steels [46], twinning-induced plasticity (TWIP) steels [54], and nickel-based superalloys [55][56][57] .…”

“…11. Comparison of the crack-propagation fatigue behavior of the CrCoNi MEA with theCrMnFeCoNi high-entropy alloy and several other comparable structural alloys: specifically, austenitic stainless steels[46], twinning-induced plasticity (TWIP) steels[54], and nickel-based superalloys[55][56][57] .…”

Effect of Thermal-Mechanical Treatment on the Fatigue Crack Propagation Behavior of Newly Developed Allvac 718Plus Alloy

“…It is generally agreed that coarse-grain alloys should have better resistance to time-dependent FCP than that of fine-grain alloys, although grain size has little effect on cycle-dependent FCP. For instance, Yuen's study [8] shows that by coarsening the grain size from 22 to 91 microns in alloy 718, near threshold crack growth rates were reduced and K th (threshold stress intensity range) values increased. Roughness-induced crack closure explains the influence of grain size.…”