High-Temperature Stability of Phases in Boron Containing Co-Re Alloys for Gas Turbine Applications

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61389005%3A_____%2F18%3A00499128" target="_blank" >RIV/61389005:_____/18:00499128 - isvavai.cz</a>

Result on the web

<a href="http://dx.doi.org/10.12693/APhysPolA.134.829" target="_blank" >http://dx.doi.org/10.12693/APhysPolA.134.829</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.12693/APhysPolA.134.829" target="_blank" >10.12693/APhysPolA.134.829</a>

Result language

angličtina

Original language name

High-Temperature Stability of Phases in Boron Containing Co-Re Alloys for Gas Turbine Applications

Original language description

Co-Re-based alloys are candidates for high-temperature applications in gas turbines. The addition of boron largely increases their ductility. The stability of the Co-solid solution matrix and of the strengthening TaC minority phase at the foreseen alloy operation temperatures (>= 1200 degrees C), potentially influenced by the presence of boron, has to be considered. The hcp to fcc transformation of the Co-solid solution matrix and the TaC minority phase evolution was thus investigated in Co-Re-Ta-C alloy with varying boron addition by in situ neutron diffraction at temperatures up to 1500 degrees C in high vacuum furnace. The neutron diffraction showed that the boron addition has no significant influence on TaC volume fraction during heating to high temperatures. In 0, 0.1, and 0.4 at.% B alloys, a strong decrease of the TaC volume fraction was observed above 1300 degrees C. Nevertheless, TaC has significant volume fraction up to that temperature and, therefore, can be effective for strengthening. The measurements further showed that while a small amount of boron addition (0.1 at.% B) has no influence on the matrix transformation and its hysteresis, a large boron addition (0.4 at.% B) influences the matrix transformation temperature significantly (lowers it by about 100 K) and, moreover, boron promotes massive Co sublimation at very high temperatures (>= 1470 degrees C). Further, re-appearance of the hcp phase around 1400 degrees C in 0.4 at.% B alloy was observed and explained by a slow sublimation of Co in high vacuum. It is not a problem from the technological point of view as vacuum is not a turbine operation condition, and as the high-temperature components are regularly protected by a coating.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

20301 - Mechanical engineering

Project

Result was created during the realization of more than one project. More information in the Projects tab.

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2018

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Acta Physica Polonica. A

ISSN

0587-4246

e-ISSN

—

Volume of the periodical

134

Issue of the periodical within the volume

3

Country of publishing house

PL - POLAND

Number of pages

9

Pages from-to

829-837

UT code for WoS article

000453257500050

EID of the result in the Scopus database

2-s2.0-85058933773