About this Abstract |
Meeting |
MS&T22: Materials Science & Technology
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Symposium
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Additive Manufacturing of Metals: Microstructure, Properties and Alloy Development
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Presentation Title |
Microstructure and Mechanical Properties of Co-based Superalloy with γ/γ' Microstructure Fabricated by Laser Powder-bed Fusion |
Author(s) |
Hyeji Im, Chuan Liu, Carelyn Campbell, David Dunand |
On-Site Speaker (Planned) |
Hyeji Im |
Abstract Scope |
Cobalt-based superalloys with high tungsten content can operate at higher temperatures as compared to Ni-based superalloys, thus improving efficiency of gas turbines and jet engines. Additively-manufactured Co-based superalloys can help overcome the challenges of poor machinability and difficulties casting complex, thin-walled geometries. However, cracking during additive fabrication is a significant barrier for further development. A set of prototype Co-base superalloys (Co-Ni-Al-W) were chosen using CALPHAD-based thermodynamic predictions to minimize the freezing range and maximize the γ' fraction for the given alloy system. The prototype alloys were fabricated via laser powder-bed fusion and heat-treated. Microstructural characterization after laser melting and heat treatments demonstrated a crack-free, fully-dense alloy. We present evolution of γ' precipitation on aging and mechanical properties. This research was funded through the U.S. Department of Commerce, National Institute of Standards and Technology (NIST) via award 70NANB14H012 as part of the Center for Hierarchical Material Design (CHiMaD). |