Friction stir processing (FSP) and superplasticity
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Authors
McNelley, T.R.
Subjects
Friction stir processing
Recrystallization
Grain refinement
Microstructure homogenization
Particle refinement
Microstructure stability
Superplasticity
Recrystallization
Grain refinement
Microstructure homogenization
Particle refinement
Microstructure stability
Superplasticity
Advisors
Date of Issue
2015
Date
Publisher
Language
Abstract
FSP is an allied technology of friction stir welding (FSW). The development and applications of these technologies are reviewed and additional considerations such as processing pattern and step over distance between successive passes in FSP are discussed. The deformation field for a rotating and advancing tool is not symmetric about the axis of tool motion. Thus, various spiral patterns with step over distances less than the tool pin diameter result in replacement of advancing interfaces (tool tangential velocity and traversing speed add) retreating interfaces (tool tangential velocity and traversing speed subtract) and greater homogeneity of the resulting stir zone microstructures. Microstructures formed as a result FSP often exhibit refined and uniform distributions of non-deforming constituents as well as highly refined grain structures, and superplastic response following FSP of wrought 7XXX and 5XXX Al alloys has been achieved. The application of multi-pass FSP to cast metals, including continuously cast (CC) AA5083 and AA356 as well as a Na modified Al-7Si will be summarized and the conversion of as-cast microstructures to a wrought condition in the absence of external shape change will be shown. Grain refinement is the result of recrystallization during the rapid thermomechanical cycle of FSP. The mechanisms involved in homogenization of constituent particle distributions remains to be determined. The FSP-induced superplastic response of the AA5083 will be documented. In contrast, grain refinement in the Na modified Al-7Si alloy was insufficient to support superplasticity.
Type
Article
Description
Series/Report No
Department
Mechanical and Aerospace Engineering
Organization
Naval Postgraduate School (U.S.)
Identifiers
NPS Report Number
Sponsors
General Motors Corporation
Office of Naval Research
Office of Naval Research
Funding
Format
7 p.
Citation
T.R. McNelley, "Friction stir processing (FSP) and superplasticity," Letters on Materials v. 5, no.3 (2015), pp. 246-252.
Distribution Statement
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.