کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1446855 988627 2011 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
In situ synchrotron X-ray imaging of high-cycle fatigue crack propagation in single-crystal nickel-base alloys
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد سرامیک و کامپوزیت
پیش نمایش صفحه اول مقاله
In situ synchrotron X-ray imaging of high-cycle fatigue crack propagation in single-crystal nickel-base alloys
چکیده انگلیسی

Fatigue crack propagation in single-crystal nickel-base superalloys was studied in situ with synchrotron X-ray imaging in a very high-cycle regime. Experiments were performed at ambient temperature with a newly developed portable ultrasonic fatigue instrument. The fatigue apparatus produced stable fatigue crack propagation with positive mean stresses for specimens as thin as 150 μm at a loading frequency of 20 kHz. Fatigue cracks propagated in a mixed-mode crystallographic manner along {1 1 1} slip planes. Phase-contrast imaging permitted analysis of the interaction of the crack front with microstructural features. Three-dimensional linear elastic finite-element analyses were performed to investigate the driving forces for crack propagation in the sheet specimen geometry. For the experimental conditions examined, fatigue crack growth is driven by the resolved shear and normal stresses on the active crack tip slip systems. An octahedral stress intensity is proposed as the relevant driving force for crack growth which determines the fatigue crack growth plane in nickel-base single crystals at room temperature.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Acta Materialia - Volume 59, Issue 13, August 2011, Pages 5103–5115
نویسندگان
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