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

Kód výsledku v 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>

Výsledek na webu

<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>

Jazyk výsledku

angličtina

Název v původním jazyce

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

Popis výsledku v původním jazyce

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.

Název v anglickém jazyce

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

Popis výsledku anglicky

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.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

20301 - Mechanical engineering

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

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

Rok uplatnění

2018

Kód důvěrnosti údajů

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

Název periodika

Acta Physica Polonica. A

ISSN

0587-4246

e-ISSN

—

Svazek periodika

134

Číslo periodika v rámci svazku

3

Stát vydavatele periodika

PL - Polská republika

Počet stran výsledku

9

Strana od-do

829-837

Kód UT WoS článku

000453257500050

EID výsledku v databázi Scopus

2-s2.0-85058933773