Presence of Oxygen in Ti-Al-C MAX Phases-Based Materials and their Stability in Oxidizing Environment at Elevated Temperatures
T. Prikhnaa, O. Ostash b, V. Sverdun a, M. Karpets a, T. Zimych a, A. Ivasyshin b, T. Cabioc'h c, P. Chartier c, S. Dub a, L. Javorska d, V. Podgurska b, P. Figel d, J. Cyboroń d, V. Moshchil a, V. Kovylaev e, S. Ponomaryov e, V. Romaka f, T. Serbenyuk a and A. Starostina a
aInstitute for Superhard Materials of the National Academy of Sciences of Ukraine, 2 Avtozavodskaya Str., Kiev, 04074, Ukraine
bKarpenko Physical-Mechanical Institute of the National Academy of Sciences of Ukraine, 5, Naukova Str. Lviv, 79060, Ukraine
cUniversité de Poitiers, CNRS/Laboratoire PHYMAT, UMR 6630 CNRS Université de Poitiers SP2MI, BP 30179, F-86962 Chasseneuil Futuroscope Cedex, France
dThe Institute of Advanced Manufacturing Technology, Wroclawska 37A, 30-011 Krakow, Poland
eEDL "Proton 21", 48a, Chernovola Str., Kiev's region 08132, Vishnevoe, Ukraine
fLviv Polytechnic National University, 12 Bandera Str., Lviv, 79013, Ukraine
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The Ti3AlC2-, (Ti,Nb)3AlC2- and Ti2AlC-based materials turned out to be more resistant than Crofer JDA steel in oxidizing atmosphere as 1000 h long tests at 600°C have shown. But the amounts of oxygen absorbed by the materials during testing were different. The Ti2AlC-based material demonstrated the lowest oxygen uptake, (Ti,Nb)3AlC2-based absorbed a somewhat higher amount and the highest amount was absorbed by Ti3AlC2-based material. Scanning electron microscopy and the Auger study witnessed that amounts of oxygen in the MAX phases before the exposure in air were as well different: the approximate stoichiometries of the matrix phases of materials were Ti3.1-3.2AlC2-2.2, Ti1.9-4Nb0.06-0.1AlC1.6-2.2O0.1-1.2 and Ti2.3-3.6AlC1-1.9O0.2-0.6, respectively. The higher amount of oxygen present in the MAX phase structures may be the reason for higher resistance to oxidation during long-term heating in air at elevated temperature. The studied materials demonstrated high stabilities in hydrogen atmosphere as well. The bending strength of the Ti3AlC2- and (Ti,Nb)3AlC2-based materials after keeping at 600°C in air and hydrogen increased by 10-15%, but the highest absolute value of bending strength before and after being kept in air and hydrogen demonstrated the Ti2AlC-based material (about 590 MPa).

DOI: 10.12693/APhysPolA.133.1108
topics: Ti-Al-C MAX phases, high- temperature resistance in air and hydrogen, hot pressing, bending strength