Developing a Superplastic Forming Capability in Nanometals
|Cheng Xu 1, Minoru Furukawa 2, Zenji Horita 3, Terence G. Langdon 1|
1. University of Southern California, Departments of Aerospace & Mechanical Engineering and Materials Science, Los Angeles, CA, United States
Equal-Channel Angular Pressing (ECAP) is a processing procedure in which a sample is pressed through a die constrained within a channel that is bent through an abrupt angle generally equal to, or very close to, 90o. An extensive set of experimental data has now established that ECAP processing is remarkably successful in significantly refining the grain size of metallic alloys to the submicrometer or nanometer range. Additional advantages of ECAP processing include the ability to produce large bulk samples containing no residual porosity and a potential for varying the processing conditions in order to produce samples having different distributions of the grain boundary misorientations. This paper describes the ECAP technique and other similar processing procedures and shows that processing in this way provides a potential for achieving high superplastic ductilities at elevated temperatures. In addition, since these high ductilities are achieved at exceptionally rapid strain rates, typically about two orders of magnitude faster than in conventional superplasticity, there is a potential for making use of these materials in industrial superplastic forming operations. Examples are presented both for special alloys produced in the laboratory and for alloys available from commercial sources.
Presentation: invited oral at E-MRS Fall Meeting 2003, Symposium G, by Terence G. Langdon
See On-line Journal of E-MRS Fall Meeting 2003
Submitted: 2003-04-14 13:27 Revised: 2009-06-08 12:55
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