Integrative design of novel Mo-Si-based alloys and protective coatings for high temperature structural applications

• Applicants: Professor Dr.-Ing. Hans Jürgen Christ, since 8/2021; Professor Dr.-Ing. Martin Heilmaier; Professor Dr. Uwe Schulz
• Subject Area: Coating and Surface Technology ; Metallurgical, Thermal and Thermomechanical Treatment of Materials ; Thermodynamics and Kinetics as well as Properties of Phases and Microstructure of Materials
• Term: from 2017 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 386184182

• Final Report Year: 2023

Final Report Abstract

Mo-silicide based alloys with high Ti-concentrations are a new class of high-temperature materials with promising properties. In particular, these multiphase alloys are more creep resistant than currently used Ni-base single crystals and exhibit good oxidation resistance at temperatures beyond 1000°C. At moderate temperatures, however, they suffer from catastrophic oxidation (pesting) and the intrinsic oxidation resistance is low. The overarching goal of this proposal was still the integrative development of a technically relevant Mo-Si-B-Ti alloy combined with an adapted coating system which provides oxidation and corrosion protection in dry and wet environments in a temperature range between 600 and 1300°C. The most relevant results are as follows: (1) B and Fe can be omitted as alloying elements enabling a simplified alloy design. (2) The systematic variation of the Ti content identified Ti concentrations establishing eutectic-eutectoid composite microstructures, which are pesting resistant as well as possess a very good creep resistance at 1200°C. (3) Because of the corresponding high Ti contents the obtained densities are favorably low with 6,2 and 7,7 g/cm³ against state of the art Ni-base superalloys. (4) The application of protective coatings such as Si, YbDS, YbMS significantly enhances oxidation resistance in both dry and wet atmospheres, Yb-silicates can be produced by reactive sputtering. (5) Differences in oxidation behaviour among the alloys are primarily attributed to different Ti contents. (6) The developed coating system protects the alloys against pest oxidation and show good high temperature stability.

Publications

• Characterisation of the oxidation and creep behaviour of novel Mo-Si-Ti alloys, Intermetallics, Bad Staffelstein, Deutschland
  S. Obert; L. Alavi; A. Kauffmann & M. Heilmaier
  
• Charakterisierung von neuen, feinstrukturierten Mo-Si-Ti Legierungen für den Hochtemperatureinsatz, DGM Fachausschusssitzung Intermetallische Phasen, Hanau, Deutschland (2019)
  S. Obert, L. Alavi, A. Kauffmann & M. Heilmaier
  
• Entwicklung von modernen Mo-Si-Ti Legierungen für Hochtemperaturanwendungen, Werkstoffwoche Dresden 2019, Dresden, Deutschland (2019)
  S. Obert, L. Alavi, L. Winheim, A. Kauffmann & M. Heilmaier
  
• Oxidation protection for Mo-based alloys by magnetron sputtered Si-based coatings, Beyond Nickel-Based Superalloys III, Nara, Japan (2019)
  R. Anton, V. Leisner, U. Schulz, S. Obert & M. Heilmaier
  
• Characterisation of the oxidation and creep behaviour of novel Mo-Si-Ti alloys. Acta Materialia, 184, 132-142.
  Obert, Susanne; Kauffmann, Alexander & Heilmaier, Martin
  
• Creep performance of pestingresistant Mo-Si-Ti alloys, Materials Research Society Fall Meeting (MRS), online, (2020)
  S. Obert, A. Kauffmann, R. Pretzler, D. Schliephake & M. Heilmaier
  
• Effect of Water Vapor on the Oxidation Behavior of the Eutectic High‐Temperature Alloy Mo‐20Si‐52.8Ti. Advanced Engineering Materials, 22(7).
  Weber, Matthias; Gorr, Bronislava; Christ, Hans-Jürgen; Obert, Susanne; Kauffmann, Alexander & Heilmaier, Martin
  
• Entwicklung und Legierungsdesign von Ti-Mo-Si Legierungen für den Hochtemperatureinsatz, DGM Fachausschusssitzung Intermetallische Phasen, Nürnberg, Deutschland (2020)
  S. Obert, A. Kauffmann, S. Schellert, M. Weber & M. Heilmaier
  
• Magnetron Sputtered Silicon Coatings as Oxidation Protection for Mo‐Based Alloys. Advanced Engineering Materials, 22(7).
  Anton, Ronja; Laska, Nadine; Schulz, Uwe; Obert, Susanne & Heilmaier, Martin
  
• On the chemical and microstructural requirements for the pesting-resistance of Mo–Si–Ti alloys. Journal of Materials Research and Technology, 9(4), 8556-8567.
  Obert, Susanne; Kauffmann, Alexander; Seils, Sascha; Schellert, Steven; Weber, Matthias; Gorr, Bronislava; Christ, Hans-Jürgen & Heilmaier, Martin
  
• Advanced design of oxidation protection coatings for Mo-based alloys by magnetron sputtering, High-Temperature Corrosion and Protection of Materials (HTCPM 2021), L‘ile des Embiez, France (online) (2021)
  R. Anton, S. Hüning, N. Laska, U. Schulz, S. Obert, A. Kauffmann, M. Heilmaier, M. Weber & B. Gorr
  
• Graded PVD Mo-Si interlayer between Si coating and Mo-Si-B alloys: Investigation of oxidation behaviour. Corrosion Science, 192, 109843.
  Anton, Ronja; Hüning, Steffen; Laska, Nadine; Weber, Matthias; Schellert, Steven; Gorr, Bronislava; Christ, Hans-Jürgen & Schulz, Uwe
  
• Microstructural and chemical constitution of the oxide scale formed on a pesting-resistant Mo-Si-Ti alloy. Corrosion Science, 178, 109081.
  Obert, Susanne; Kauffmann, Alexander; Seils, Sascha; Boll, Torben; Kauffmann-Weiss, Sandra; Chen, Hans; Anton, Ronja & Heilmaier, Martin
  
• The Creep and Oxidation Behaviour of Pesting-Resistant (Mo,Ti)5Si3-Containing Eutectic-Eutectoid Mo-Si-Ti Alloys. Metals, 11(1), 169.
  Obert, Susanne; Kauffmann, Alexander; Pretzler, Rupert; Schliephake, Daniel; Hinrichs, Frauke & Heilmaier, Martin
  
• The effect of water vapour on the high temperature oxidation behaviour of Mo-20Si-52,8Ti, High-Temperature Corrosion and Protection of Materials (HTCPM 2021), L‘ile des Embiez, France (online) (2021)
  M. Weber, B. Gorr, H.-J. Christ, R. Anton, N. Laska, U. Schulz, S. Obert, A. Kauffmann & M. Heilmaier
  
• Development and characterization of an Environmental Barrier Coating system for Mo-based alloys using magnetron sputtering, International Conference on Metallurgical Coatings and Thin Films (ICMCTF), San Diego, USA (2022)
  R. Anton, V. Leisner, N. Laska & U. Schulz
  
• Interface reactions of magnetron sputtered Si-based dual layer coating systems as oxidation protection for Mo-Si-Ti alloys. Surface and Coatings Technology, 444, 128620.
  Anton, Ronja; Hüning, Steffen; Laska, Nadine; Weber, Matthias; Schellert, Steven; Gorr, Bronislava; Christ, Hans-Jürgen; Heilmaier, Martin & Schulz, Uwe
  
• Phase Continuity, Brittle to Ductile Transition Temperature, and Creep Behavior of a Eutectic Mo–20Si–52.8Ti Alloy. Advanced Engineering Materials, 24(11).
  Tirunilai, Aditya Srinivasan; Hinrichs, Frauke; Schliephake, Daniel; Engstler, Michael; Mücklich, Frank; Obert, Susanne; Winkens, Georg; Kauffmann, Alexander & Heilmaier, Martin
  
• Reactive Sputtered Ytterbium Silicate Environmental Barrier Coatings for Protection of Mo-Si-Based Alloys. Coatings, 12(8), 1086.
  Anton, Ronja; Leisner, Vito; Laska, Nadine & Schulz, Uwe
  
• Characterization of the oxidation behavior of non-coated and Si-coated Mo-Si-Ti alloys in dry and wet atmospheres, The 20th International Microscopy Congress (IMC20), Busan, Republic of Korea (2023)
  M. Weber, S. Schellert, H.-J. Christ, A. S. Tirunilai, A. Kauffmann, M. Heilmaier, R. Anton, N. Laska, U. Schulz & B. Gorr
  
• The oxidation behavior of the eutectic alloy Mo-20Si-52.8Ti in dry and wet atmospheres, The Minerals, Metals & Materials Society Annual Meeting & Exhibition (TMS), San Diego, USA (2023)
  M. Weber, S. Schellert, H.-J. Christ, A. S. Tirunilai, A. Kauffmann, M. Heilmaier & B. Gorr