Additive Manufacturing of Functionally Graded Oxide Dispersion-Strengthened Superalloys
Abstract
Oxide dispersion-strengthened (ODS) superalloys, comprising a dispersion of oxide nanoparticles in a metallic matrix, have exception,al creep and oxidation resistance which make them ideal for advanced propulsion and thermal protection systems. In these and other a,pplications, ODS superalloys can enable higher operating temperatures and enhanced reliability, with corresponding improvements in s,afety and efficiency. However, the cost, complicated processing, and limited formability of ODS superalloys have hindered their adop,tion. This proposal aims to overcome these processing challenges by consolidating ODS powder feedstock using selective laser melting, (SLM), a melt-based additive manufacturing (AM) method. The underlying hypothesis is that SLMs combination of rapid solidification, conditions, turbulent liquid phase mixing, and extreme thermal cycling can suppress oxide agglomeration and coarsening while trappi,ng in a high dislocation density to enable directional recrystallization during post-processing heat treatments. The scientific goal, of this proposal is thus to elucidate the effects of SLM and directional recrystallization (DRX) heat treatments on the structure a,nd high-temperature mechanical properties of ODS superalloys. In pursuit of this goal, the project will begin with a parameter study, to determine SLM and DRX conditions that give fully dense components with a spatially uniform dispersion of nanoscale oxides and a,columnar grain structure (Objective 1). Next, the microstructure and high-temperature mechanical properties of the as-printed and di,rectionally recrystallized materials will be characterized in detail (Objective 2). Finally, these experimental results will be comb,ined with multi-physics simulations of SLM and DRX to elucidate the physical mechanisms that drive structural evolution during melt-,based AM and subsequent post-processing of ODS alloys (Objective 3). The process-structure-mechanical property linkages established,through this research will enable a new class of net-shaped ODS alloys with exceptional high-temperature creep strength and oxidatio,n resistance for demanding Navy applications. This abstract/summary is Approved for Public Release.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Dec 10, 2021
- Source ID
- N000142212036
Entities
People
- Zachary C. Cordero
Organizations
- Massachusetts Institute of Technology
- Office of Naval Research
- United States Navy