Rapid Solidification in Bulk Ti-Nb Alloys by Single-Track Laser Melting
- 655 Downloads
Single-track laser melting experiments were performed on bulk Ti-Nb alloys to explore process parameters and the resultant macroscopic structure and microstructure. The microstructures in Ti-20Nb and Ti-50Nb (at.%) alloys exhibited cellular growth during rapid solidification, with average cell size of approximately 0.5 µm. Solidification velocities during cellular growth were calculated from images of melt tracks. Measurements of the composition in the cellular and intercellular regions revealed nonequilibrium partitioning and its dependence on velocity during rapid solidification. Experimental results were used to benchmark a phase-field model to describe rapid solidification under conditions relevant to additive manufacturing.
This work was performed under the auspices of the U.S. Department of Energy (DOE) by Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344. Work was supported by the Laboratory Directed Research and Development (LDRD) Program under project tracking Code 18-SI-003. TEM work was performed at the Colorado School of Mines and was supported by A.J.C.’s Early Career Award from the U.S. DOE, Office of Science, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, Award No. DE-SC0016061. J.-L.F. acknowledges support from the Exascale Computing Project (17-SC-20-SC), a collaborative effort of the U.S. DOE, Office of Science, and the National Nuclear Security Administration. The authors thank Nick Teslich at LLNL for his impeccable work on the FIB specimen preparation for TEM and John Mangum at CSM for his help with the NanoMill®.
- 4.T. Kelner, The FAA cleared the first 3D printed part to fly in a commercial jet engine from GE (2015). https://www.ge.com/reports/post/116402870270/the-faa-cleared-the-first-3d-printed-part-to-fly-2/. Accessed Dec 2017.
- 31.A.T. D’Annessa, Weld. J., Weld. Res. Suppl. 49, 41 (1970).Google Scholar
- 34.W. Kurz and D.J. Fisher, Fundmentals of Solidification (Zürich: Trans Tech, 1984).Google Scholar
- 36.J.D. Hunt, in Proceedings of the International Conference on Solidification and Casting of Metals, The Metals Society, London, 1979.Google Scholar
- 40.C. Huang and S. Kou, Weld. J. 80, 46 (2001).Google Scholar
- 44.H. Okamoto, Nb-Ti Phase Diagram, ASM International Materials Park, OH (2016). http://www.asminternational.org. Accessed Dec 2017.