title: Ultralow-temperature superplasticity in nanoceramic composites.
abstract: We report the successful demonstration for low-temperature and high-strain-rate superplastic forming of nanoceramic composites for the first time. Porous preforms of nanoceramic composites that were partially densified at low temperatures were superplastically deformed by SPS at the record low temperatures of approximately 1000 to 1050 degrees C, which are comparable to those of Ni-based superalloys. The maximum strain rate achieved is over 10(-2) s(-1), and a compressive strain over 200% can be obtained without cracking. The final products have nanosized grains with excellent optical properties. The present findings present a new strategy for nanoceramic superplasticity, demonstrating that a more practical application of nanoceramic superplasticity is not in the shaping of already-dense materials but in the near-net-shape forming of partially dense parts.
authors.affiliation: Department of Chemical and Biological Engineering, the University of Colorado at Boulder, Boulder, CO 80309, USA. guodong.zhan@colorado.edu
authors.forename: Guo-Dong
authors.initials: GD
authors.lastname: Zhan
authors.forename: Javier E
authors.initials: JE
authors.lastname: Garay
authors.forename: Amiya K
authors.initials: AK
authors.lastname: Mukherjee
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry*; D002516:Ceramics / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D004548:Elasticity; D006244:Hardness; D008422:Materials Testing; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods*; D011208:Powders; D013499:Surface Properties; D013696:Temperature
chemical_list: D011208:Powders; D000537:Aluminum Oxide