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

2014 ◽  
Author(s):  
Osamu Umezawa ◽  
Motoaki Morita ◽  
Takayuki Yuasa ◽  
Satoshi Morooka ◽  
Yoshinori Ono ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Fatigue Crack ◽  
Low Temperature ◽  
Crack Generation ◽  
Alpha Titanium ◽  
Heterogeneous Deformation ◽  
Fatigue Crack Generation

A Subsurface Fatigue Crack Generation Model in near Alpha Titanium at Low Temperature

2018 ◽  
Vol 941 ◽  
pp. 1336-1341
Author(s):  
Osamu Umezawa ◽  
Wei Bo Li
Keyword(s):  
Shear Stress ◽  
Fatigue Crack ◽  
Basal Plane ◽  
Main Crack ◽  
Generation Model ◽  
Strain Accumulation ◽  
Crack Generation ◽  
Alpha Titanium ◽  
Microcrack Growth ◽  
Fatigue Crack Generation

The subsurface fatigue crack generation processes in near α type titanium alloy were divided into four steps: (1) development of a saturated dislocation structure by cyclical micro-plastic strain accumulation, (2) generation of localized slip and/or microcracking to relax the stress concentration in the vicinity of a boundary, (3) microcrack growth and transition to main crack, and (4) crack propagation. The experimentals on transgranular facets formation in Ti-Fe-O alloy were reviewed and a subsurface fatigue crack generation model was discussed. The 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. A combination of the shear stress and tensile stress normal to the basal plane may give a trigger of the (0001) microcracking in the recrystallized α grain. The localized shear stress following slip off on the basal plane was activated at the microcrack tip in the recrystallizedαgrain, and the microcrack grew into the recrystallized α grain to form (0001) transgranular facet.

Time to fatigue-crack generation and speed of fatigue-crack growth in steels 08kp and U8

1976 ◽  
Vol 11 (4) ◽  
pp. 421-423
Author(s):  
V. I. Pokhmurskii ◽  
M. O. Levitskii ◽  
S. I. Mikitishin
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Crack Generation ◽  
Fatigue Crack Generation
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