کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1448307 988670 2009 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Low cycle fatigue behaviour of a low interstitial Ni-base superalloy
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد سرامیک و کامپوزیت
پیش نمایش صفحه اول مقاله
Low cycle fatigue behaviour of a low interstitial Ni-base superalloy
چکیده انگلیسی

The low cycle fatigue behaviour of precipitation strengthened nickel-base superalloy 720Li containing a low concentration of interstitial carbon and boron was studied at 25, 400 and 650 °C. Cyclic stress response at all temperatures was stable under fully reversed constant total strain amplitude (Δε/2) when Δε/2 ⩽ 0.6%. At Δε/2 > 0.6%, cyclic hardening was followed by softening, until fracture at 25 and 650 °C. At 400 °C, however, cyclic stress plateaued after initial hardening. Dislocation–dislocation interactions and precipitate shearing were the micromechanisms responsible for the cyclic hardening and softening, respectively. The number of reversals to failure vs. plastic strain amplitude plot exhibits a bilinear Coffin–Manson relation. Transmission electron microscopy substructures revealed that planar slip was the major deformation mode under the conditions examined. However, differences in its distribution were observed to be the cause for the bilinearity in fatigue lives. The presence of fine deformation twins at low Δε/2 at 650 °C suggests the role of twinning in homogenization of cyclic deformation.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Acta Materialia - Volume 57, Issue 12, July 2009, Pages 3450–3459
نویسندگان
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