Polycrystalline microstructure, cubic elasticity, and nucleation of high-cycle fatigue cracks
نویسندگان
چکیده
منابع مشابه
Mixed-mode, high-cycle fatigue-crack growth thresholds in Ti– 6Al–4V: Role of small cracks
There have been few studies to date describing fatigue-crack propagation thresholds under mixed-mode loading conditions in the presence of cracks, that are small as compared to the characteristic microstructural dimensions. To address this need, the variation in mixed-mode, high-cycle fatigue-crack growth thresholds with crack size is reported for a Ti-6Al-4V turbine blade alloy with a fine-gra...
متن کاملFurther considerations on the high-cycle fatigue of micron-scale polycrystalline silicon
Bulk silicon is not susceptible to high-cycle fatigue but micron-scale silicon films are. Using polysilicon resonators to determine stress-lifetime fatigue behavior in several environments, oxide layers are found to show up to four-fold thickening after cycling, which is not seen after monotonic loading or after cycling in vacuo.We believe that the mechanism of thin-film silicon fatigue is ‘‘re...
متن کاملHigh-cycle Fatigue in Micron-scale Structural Films of Polycrystalline Silicon: a Reaction-layer Failure Mechanism
A study has been made of high-cycle fatigue in 2-μm thick structural films of ntype, polycrystalline silicon for MEMS applications. Using an “on-chip” test structure resonating at ~40 kHz, such thin-film polysilicon is shown to display “metal-like” stress-life fatigue behavior in room air environments, with failures occurring after lives in excess of 10 cycles at stresses as low as half the fra...
متن کاملHigh-Cycle Fatigue of Polycrystalline Silicon Thin Films in Laboratory Air
When subjected to alternating stresses, most materials degrade, e.g., suffer premature failure, due to a phenomenon known as fatigue. It is generally accepted that in brittle materials, such as ceramics, cyclic fatigue can only take place where there is some degree of toughening, implying that premature fatigue failure would not be expected in polycrystalline silicon where such toughening is ab...
متن کاملForeign-object damage and high-cycle fatigue: role of microstructure in Ti–6Al–4V
The objective of this study was to evaluate the influence of microstructure on the susceptibility to high-cycle fatigue (HCF) failure in Ti–6Al–4V following foreign-object damage (FOD), specifically by comparing a fine-grained bi-modal microstructure with a coarse grained lamellar microstructure. FOD was simulated by high-velocity impacts of steel spheres on a flat surface. This caused a marked...
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ژورنال
عنوان ژورنال: International Journal of Fracture
سال: 2006
ISSN: 0376-9429,1573-2673
DOI: 10.1007/s10704-006-9005-x