Schroers, Jan and Veazey, Chris and Demetriou, Marios D. and Johnson, William L. (2004) Synthesis method for amorphous metallic foam. Journal of Applied Physics, 96 (12). pp. 7723-7730. ISSN 0021-8979. http://resolver.caltech.edu/CaltechAUTHORS:SCHRjap04
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A synthesis method for the production of amorphous metallic foam is introduced. This method utilizes the thermodynamic stability and thermoplastic formability of the supercooled liquid state to produce low-density amorphous metallic foams in dimensions that are not limited to the critical casting thickness. The method consists of three stages: the prefoaming stage, in which a large number of small bubbles are created in the equilibrium liquid under pressure; the quenching stage, in which the liquid prefoam is quenched to its amorphous state; the foam expansion stage, in which the amorphous prefoam is reheated to the supercooled liquid region and is processed under pressures substantially lower than those applied in the prefoaming step. Results from a dynamic model suggest that the foam expansion process is feasible, as the kinetics of bubble expansion in the supercooled liquid region are faster than the kinetics of crystallization. Within the proposed synthesis method, bulk amorphous foam products characterized by bubble volume fractions of as high as 85% are successfully produced.
|Additional Information:||©2004 American Institute of Physics. Received 23 June 2004; accepted 21 September 2004. This work was supported by Liquidmetal Technology and NASA Marshall Space Flight Center. Dr. William F. Kaukler of the Center for Microgravity and Materials Research at The University of Alabama in Huntsville is acknowledged for engineering the compact-resistance heater. The authors express their gratitude to Kristen Virdone and Joan Christodoulou for technical assistance.|
|Subject Keywords:||palladium alloys; nickel alloys; copper alloys; phosphorus alloys; liquid alloys; porous materials; bubbles; foams; materials preparation; amorphous state; thermal stability; quenching (thermal); crystallisation; supercooling|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||07 Aug 2006|
|Last Modified:||26 Dec 2012 08:58|
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