Experimental and numerical engineering of novel eutectic high melting Mo-Si-Ti alloys processed by additive manufacturing: microstructure, texture and ensuing properties

• Applicant: Professor Dr.-Ing. Martin Heilmaier
• Subject Area: Metallurgical, Thermal and Thermomechanical Treatment of Materials ; Mechanical Properties of Metallic Materials and their Microstructural Origins
• Term: from 2019 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 424801257

• Final Report Year: 2024

Final Report Abstract

Manufacturing of larger complex parts of oxidation and creep resistant Mo-Si-Ti alloys is difficult by conventional processing. Therefore, additive manufacturing (AM) by Direct Energy Deposition (DED-LB) was applied in this project to process Mo-20Si-52.8Ti (at.%) alloy consisting of a (Mo,Ti,Si)ss and (Ti,Mo)5Si3 and to investigate the process-structure-property (PSP) correlation. Furthermore, directional solidification (DS) was used to evaluate the effect of much slower cooling rates on the PSP in comparison to DED-LB and conventional cast metallurgy. It was found that the high processing temperatures during DED-LB lead to the formation of a high number of (Ti,Mo)5Si3 precipitates, which are also observed during creep at 1200°C of cast material. This and the higher phase boundary density in DED-LB material are found to reduce the strength and creep resistance. The (Mo,Ti,Si)ss and (Ti,Mo)5Si3 phase establish a distinct orientation relationship (OR) during solidification in both processes, DED- LB and DS. However, no influence of the OR on the mechanical properties was observed. Additional Mo-Si-Ti alloys with 72 at.% Ti were designed for DS experiments and an increase in fracture toughness was observed.

Publications

• Flexible Powder Production for Additive Manufacturing of Refractory Metal-Based Alloys. Metals, 11(11), 1723.
  Hinrichs, Frauke; Kauffmann, Alexander; Schliephake, Daniel; Seils, Sascha; Obert, Susanne; Ratschbacher, Karin; Allen, Melissa; Pundt, Astrid & Heilmaier, Martin
  
• 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
  
• The Creep‐Induced Micro‐ and Nanostructural Evolution of a Eutectic Mo–Si–Ti Alloy at 1200 °C. Advanced Engineering Materials, 26(17).
  Thota, Hemanth; Schliephake, Daniel; Kauffmann, Alexander; Wu, Huichao; Pundt, Astrid; Heilmaier, Martin & Eggeler, Yolita M.
  
• Unveiling the Intricacies of a Ductile‐Phase Toughened Intermetallic: An In‐Depth Exploration of a Eutectic Mo–Si–Ti Alloy and its Mechanical Behavior. Advanced Engineering Materials, 26(17).
  Vikram, Raja Jothi; Aramanda, Shanmukha Kiran; Schliephake, Daniel; Kauffmann, Alexander; Choudhury, Abhik; Heilmaier, Martin & Suwas, Satyam