Slip and fatigue crack formation processes in an α/β titanium alloy in relation to crystallographic texture on different scales

Analysis of Subsurface Fatigue Crack Generation in Ti–Fe–O Alloy at Low Temperature

“…The localized slip following slip off on the basal plane must be activated in the recrystallized α grain for the microcrack growth, where the shear stress to the basal plane should act at the microcrack tip. 16) Bridier et al 15) suggested that the origin of fatal crack on basal plane required a combination of a high Schmid factor in addition to high elastic stiffness, including a high tensile stress normal to the basal plane, although the detected α grains with microcracks showed the basal Schmid factor in the range of 0.15-0.45. Therefore, thin β platelets which were aligned between the recrystallized α grain and the recovered α grain were responsible for the microcrack generation to form {0001} tansgranular facet in the recrystallized α grains as follows:…”

“…15) According to the full constraints model analysis, the relaxation under the simple shear mode was easier than that under the tension mode. 16) The localized basal slip on {0001} under the simple shear mode may assist the growth of microcrack.…”

Slip Deformation Analysis Based on Full Constraints Model for α-Titanium Alloy at Low Temperature

“…M max shows an increase of 0.941 relative to M at the same axis in Type 1. There are two sets of five independent slip systems for minimum work at the axis listed in Table 2 16,18) so that the f01 1 10gh11 2 20i is geometrically hard to operate. In Types 2-4, therefore, the restrictions of other slip systems result in the operation of f01 1 10gh11 2 20i because of their higher CRSSs.…”

“…16,18) In this regime, M is comparatively high regardless of the secondary slip systems' operation, and the number of active f01 1 10gh11 2 20i is mostly the same (Fig. 8).…”

Analyses of heterogeneous deformation and subsurface fatigue crack generation in alpha titanium alloy at low temperature

“…Moreover, both plastic and elastic deformations coexist in polycrystalline specimens, since the operation depends on the crystal orientation. In the stage 2), regardless of whether the origin of transgranular cracking is slip-off (slip localization) [7] or microcracking [8] on a crystal plane, the plastic deformation on the facet plane hardly yields and the elastic field normal to the facet plane has to accumulate. Table 1 represents crystallographic characterization of the transgranular facet at subsurface crack initiation sites in the references [3,7,[9][10][11][12][13][14][15][16].…”