Development of nanocrystalline structure in Cu during friction stir processing (FSP)

Abstract

The characteristics of microstructures at various locations behind the pin tool extraction site were studied in copper after FSP that had been conducted with continuous quenching to enhance cooling rates. The substructures initially formed around the pin tool consist of very small crystallites having sizes of a few tens of nanometers. It is proposed that the processing conditions result in formation of microband structures around pin tool in the presence of severe strain heterogeneity. The microbands appear as nano-scale elongated crystallites surrounded by high-angle boundaries. The elongated crystallites transform to nearly random oriented and equiaxed grain structures by shape adjustment during the initial stages of cooling from the peak temperature. Nanocrystalline structures ∼174 nm in size were produced in OFHC copper by FSP.

Department(s)

Materials Science and Engineering

Sponsor(s)

United States. Office of Naval Research
National Research Council (U.S.). Research Associateship Program

Keywords and Phrases

Friction Stir Processing (FSP); Grain Refinement; Microband; Nanocrystalline Structure; Orientation Imaging Microscopy (OIM)

International Standard Serial Number (ISSN)

0921-5093

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2011 Elsevier, All rights reserved.

Publication Date

01 Jun 2011

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