کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
10630262 991252 2005 15 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Creep of directionally solidified alumina/YAG eutectic monofilaments
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد سرامیک و کامپوزیت
پیش نمایش صفحه اول مقاله
Creep of directionally solidified alumina/YAG eutectic monofilaments
چکیده انگلیسی
Multi-phase-single crystal oxide fibers offer the best choice for reinforcing oxide matrix composites because they have superior creep resistance up to 1700 °C without significant strength loss at moderate temperatures due to growth of processing flaws. In this work, Directionally Solidified Al2O3-YAG eutectic fibers were grown at various rates by the Edge-defined, Film-fed Growth (EFG) method and their microstructure, microstructural stability and creep properties were studied. A methodology was developed in order to determine if the creep behavior of a fiber was affected by any heterogeneous coarsening defects. The creep behavior could be rationalized using a threshold stress concept with activation energy of 1100 kJ/mol K. TEM analysis of the crept fibers suggested that the Sapphire phase was deforming by a dislocation mechanism, while the YAG phase deformed by a diffusional mechanism. A creep model was developed which contained geometrical factors for describing the microstructure. Analysis of the data showed that the creep resistance would increase to single crystal values as the phase aspect ratio increased. Further, these two phases-single crystal structures exhibit a flaw-independent strength and are suggested to have a decrease in slow crack growth rate as the transverse phase size decreases.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of the European Ceramic Society - Volume 25, Issue 8, 2005, Pages 1225-1239
نویسندگان
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