ACTA

Presence of Oxygen in Ti-Al-C MAX Phases-Based Materials and their Stability in Oxidizing Environment at Elevated Temperatures

T. Prikhna^a, 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 Ti_3.1-3.2AlC_2-2.2, Ti_1.9-4Nb_0.06-0.1AlC_1.6-2.2O_0.1-1.2 and Ti_2.3-3.6AlC_1-1.9O_0.2-0.6, 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