Alumina Failure and Post-failure Oxidation in the NiCoCrAlY Alloy System at High Temperature
نویسندگان
چکیده
This paper examines the oxidation behavior of thin specimens cast NiCoCrAlY alloys at 1150 $$^\circ {\rm C}$$ through successive stages, from $${\rm Al}_2{\rm O}_3$$ growth to complete alloy conversion oxide. Five compositions were used, with varying fractions and $$\gamma$$ $$\beta$$ . The time evolution composition during was simulated using DICTRA module Thermo-Calc calculated analytically in approximation flat profiles. Simulated experimental profiles found be good agreement, indicating that phase equilibrium mass balance correctly reproduced simulations. Local variations observed thinner comparable expected uncertainty on initial specimen thickness. time-to- failure greater than this basis, suggesting additional sources variability effect. Alumina followed by a Cr}_2{\rm layer alloy–scale interface. Similarly, Cr consumption eventually led failure, Ni- Co-containing spinel oxide formed, converting interface scale–gas remaining NiCo then converted (Ni,Co)O. sequence occurred without abrupt increase gain, due continued presence remnant layer, small amount metal left oxidize when (Ni,Co)O broke scale. scale throughout stages is discussed based an analysis thermodynamic conditions
منابع مشابه
High Temperature Oxidation Behaviour of Nimonic - 115 Alloy in Presence of Sodium Salts at 850OC
The high temperature oxidation behaviour of Nimonic-115 industrial alloy has been investigated in presence of NaNO3, Na2CO3 and Na2O2 at 850oC in flowing air. The oxidation kinetics and effect of salt deposition for the period of 48 h were studied. The scale morphologies were determined on the basis of X-ray diffraction anal...
متن کاملhigh temperature oxidation behaviour of nimonic - 115 alloy in presence of sodium salts at 850oc
the high temperature oxidation behaviour of nimonic-115 industrial alloy has been investigated in presence of nano3, na2co3 and na2o2 at 850oc in flowing air. the oxidation kinetics and effect of salt deposition for the period of 48 h were studied. the scale morphologies were determined on the basis of x-ray diffraction analysis and scanning electron microscopic techniques. it has been shown t...
متن کاملhigh volatility, thick tails and extreme value theory in value at risk estimation: the case of liability insurance in iran insurance company
در این بررسی ابتدا به بررسی ماهیت توزیع خسارات پرداخته میشود و از روش نظریه مقادیر نهایی برای بدست آوردن برآورد ارزش در معرض خطر برای خسارات روزانه بیمه مسئولیت شرکت بیمه ایران استفاده میشود. سپس کارایی نظریه مقدار نهایی در برآورد ارزش در معرض خطر با کارایی سایر روشهای واریانس ، کواریانس و روش شبیه سازی تاریخی مورد مقایسه قرار میگیرد. نتایج این بررسی نشان میدهند که توزیع ،garch شناخته شده مدل...
15 صفحه اولthe relationship between academic self-concept and academic achievement in english and general subjects of the students of high school
according to research, academic self-concept and academic achievement are mutually interdependent. in the present study, the aim was to determine the relationship between the academic self-concept and the academic achievement of students in english as a foreign language and general subjects. the participants were 320 students studying in 4th grade of high school in three cities of noor, nowshah...
ذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Oxidation of Metals
سال: 2021
ISSN: ['0030-770X', '1573-4889']
DOI: https://doi.org/10.1007/s11085-021-10060-9