کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1445432 1509592 2015 19 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Three-dimensional imaging and phase-field simulations of the microstructure evolution during creep tests of 〈011〉-oriented Ni-based superalloys
ترجمه فارسی عنوان
شبیه سازی های تصویربرداری سه بعدی و شبیه سازی فاز میدان مغناطیسی تکامل ریزساختار در آزمایش های خزش فوق العاده اشعه ایکس بر مبنای نیکل
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد سرامیک و کامپوزیت
چکیده انگلیسی

Microstructure evolution during tensile creep of 〈011〉-oriented samples of first-generation Ni-based single-crystal superalloys was investigated both experimentally and numerically. Based on scanning electron microscopy and 3-D volume reconstruction using a dual-beam system, it was shown that the initially cuboidal microstructure first elongates along the cubic axis perpendicular to the tensile axis, and then coalesces along the two other cubic directions. We found that the normal to the platelets, initially close to a cubic axis, slightly rotates towards the tensile axis direction and the destabilization of the platelet microstructure appears to control the onset of the tertiary creep stage. In a second part, microstructure evolutions are analyzed using 3-D phase-field simulations. The inhomogeneous and anisotropic elastic and plastic driving forces are discussed, as well as the importance of a small misorientation of the tensile axis from the [0 1 1] direction. Surprisingly, contrary to the case of 〈100〉-oriented sample, complete rafting is not obtained in the simulations, suggesting that an additional mechanism at the level of individual dislocations could be missing. Finally, we have developed an energetic model for a perfectly rafted microstructure, which proves that plasticity in the γ   phase is at the origin of the γ/γ′γ/γ′ interface rotation during creep.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Acta Materialia - Volume 84, 1 February 2015, Pages 237–255
نویسندگان
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