Institute for Applied Materials – Materials Science and Engineering

Materials Compounds from Composite Materials - Evaluation of additive manufacturing for RM-Si(-B-X) based substrates

M.Sc. Frauke Hinrichs

Motivation

In the graduate school 2561 (Materials Compounds from Composite Materials), researchers from the Technical University Darmstadt, the DECHEMA, and KIT collaborate, to develop novel composite materials for high-temperature applications above 1300 °C in challenging atmospheric conditions. To achieve this, high melting point multi-phase materials based on refractory metal silicide systems will be prepared to serve as a substrate material to be coated with polymer-derived ceramic nanocomposites (PDC-NCs) based on Si(M)CX.

Mo-Si-Ti(-B) alloys posses outstanding microstructure stability and creep resistance at high temperatures. Furthermore, they also provide adequate deformability and toughness at ambient temperatures. Manufacturing substrates of this alloy system by Electron Beam Melting (EBM) with high pre-heating temperatures will avoid thermal cycling around the brittle-to-ductile transition temperature (DBTT) and therefore cracking of the build components.

Objectives

  • Determination of process parameters to obtain crack-free (eutectic) Mo-Ti-Si(-B) substrate with the EBM process
  • Determining the influence of process-related cooling rates and thermal gradients on the alloy’s microstructure as well as the importance of heat treatments
  • Linking the findings on local chemical composition, the lateral length scale of phases, as well as micro-texture, depending on the different processing strategies to the mechanical properties and oxidation resistance of the material

Investigations

  • Parameter study to obtain a crack- and pore-free substrates
  • O-/N-analysis for tracking the material purity during the process
  • Microstructure investigations after material manufacturing via EBM
  • Heat treatments to investigate microstructure stability

Funding

Graduate school 2561 "Materials Compounds from Composite Materials" by the Deutschen Forschungsgemeinschaft