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Lecture

WEB Thermodynamic database for the Ni-Al-Cr-Mo-O system

Wednesday (01.01.2020)
00:00 - 00:15
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A thermodynamic database for the five component Ni-Al-Cr-Mo-O system was developed. The CALPHAD approach (computer coupling of phase diagrams and thermochemistry) with sublattice models expressed in the compound energy formalism was used. The corresponding ten binary and ten ternary subsystems were taken into account and combined for computed multicomponent extensions. The database can be used to determine stability ranges of the formed intermetallic phases and oxides of engineering alloys. The phase diagrams, such as isothermal sections, isopleths and potential diagrams, as well as property diagrams and thermodynamic data can be calculated. The phase reactions of NiAl alloys with chromium and molybdenum and the isothermal oxidation behavior were studied by calculations and experimentally. Samples produced from (a) arc melting and subsequent casting and (b) from directional solidification were analyzed by electron microscopy, chemical analysis (EDX, WDX), electron backscatter diffraction (EBSD), X-ray diffraction and thermal analyses (TGA). For TGA, a thermobalance was used for investigations at temperatures of 800 °C, 1200 °C and 1300 °C and under atmosphere from Ar/O2 (13 vol.%) .

Speaker:
Prof. Dr. Hans Jürgen Seifert
Karlsruhe Institute of Technology (KIT)
Additional Authors:
  • Golnar Geramifard
    Karlsruhe Institute of Technology (KIT)
  • Dr. Peter Franke
    Karlsruhe Institute of Technology (KIT)