Exploring failure modes of alumina scales on FeCrAl and FeNiCrAl alloys in a nitriding environment
Artikel i vetenskaplig tidskrift, 2020

Two high-temperature FeCrAl and FeNiCrAl alloys were exposed in a strongly nitriding environment at 900 °C and the morphology of nitridation was studied. Quasi-in-situ experiments revealed that nitridation started at specific surface sites directly related to the alloy microstructure where the alumina scale was permeable to nitrogen. FeCrAl alloy grains with (112) orientation formed outward-growing alumina scales and were susceptible to nitridation. Outward-growing scales and substrate nitridation was also observed at chromium carbide precipitates in the FeNiCrAl alloy. Both alloys suffered nitridation at reactive element-rich (Y and Zr) inclusions larger than a certain critical size. The latter type of attack is caused by cracks and pores in the scale. The findings open new avenues of research for developing the next generation of high temperature alloys with superior properties.

High temperature oxidationNitridationAlumina scale failureCrystallographic orientationReactive elements

Författare

Anna Nooshin Mortazavi

Harvard University

Mohsen Esmaily

Massachusetts Institute of Technology (MIT)

Christine Geers

Chalmers, Kemi och kemiteknik, Energi och material, Oorganisk miljökemi

Nick Birbilis

Australian National University

Jan-Erik Svensson

Chalmers, Kemi och kemiteknik, Energi och material, Oorganisk miljökemi

Mats Halvarsson

Chalmers, Fysik, Mikrostrukturfysik

D. Chandrasekaran

Kanthal AB

Lars-Gunnar Johansson

Chalmers, Kemi och kemiteknik, Energi och material, Oorganisk miljökemi

Acta Materialia

1359-6454 (ISSN)

Vol. 201 131-146

Ämneskategorier

Materialkemi

Annan materialteknik

Metallurgi och metalliska material

DOI

10.1016/j.actamat.2020.09.058

Mer information

Senast uppdaterat

2020-11-27