کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1656994 1517603 2015 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Damage evolution of a thermal barrier coating system with 3-dimensional periodic interface roughness: Effects of roughness depth, substrate creep strength and pre-oxidation
ترجمه فارسی عنوان
تکامل آسیب سیستم پوشش حرارتی با زبری انسجام سه بعدی سه بعدی: تاثیر عمق زبری، مقاومت خزش بتونه و پیش اکسیداسیون
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد فناوری نانو (نانو تکنولوژی)
چکیده انگلیسی


• Faster oxidation at roughness valleys than at the peak positions.
• For all hexagonal and stochastically roughened samples pronounced segmentation and continuous crumbling occurred without spallation.
• Despite the partially observed strong TBC-delamination, stress relaxation avoided large area TBC-spallation during the thermal cycling.
• Pre-oxidized samples showed significantly larger delamination crack areas.

Damage evolution during thermocyclic loading of atmospheric plasma sprayed thermal barrier coating (TBC) systems with 3-dimensional (3-D) periodical quadratic, hexagonal and stochastical interface roughness was compared. Furthermore, effects of roughness depth, substrate creep strength and pre-oxidation were investigated. As substrates planar Fecralloy EisenChrom™ was used. The samples with periodical hexagonal roughness showed on average near cubic oxidation kinetics and faster oxidation at the roughness valleys than at the peaks. The coatings on all samples with 3-D quadratic roughness failed immediately after TBC-deposition. For the other profiles excessive segmentation and continuous crumbling of the TBCs occurred. However, the coatings mostly did not spall-off during 836 oxidation cycles. Thermography permitted to detect < 1 mm diameter spot-shaped initial delaminations (IDs) that formed during thermal cycling. With progressive cycling their number and area increased until they merge. The positions where IDs formed correlated with locally larger TBC thicknesses associated with the spray path during TBC deposition. Samples with pre-deposited oxide layer showed significant larger delamination areas after thermal cycling. Sample bending towards the TBC and deformation of the substrate below the TBC occurred, indicating stress relaxation. Despite the partially large delaminations, this relaxation led to the prevention of macroscopic TBC detachment and large area spallation till the end of the thermal cycling tests. Cross-sections of the 3-D periodic roughened samples revealed no effect of the roughness depth on the amount of cracking or on damage evolution after certain cycle numbers.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Surface and Coatings Technology - Volume 276, 25 August 2015, Pages 368–373
نویسندگان
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