Processing-microstructure relationships in friction stir welding of MA956 oxide dispersion streel

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Authors
Baker, Bradford W.
Menon, Sarath K.
McNelley, Terry R.
Brewer, Luke N.
El-Dasher, Bassem
Farmer, Joseph C.
Torres, Sharon G.
Mahoney, Murray W.
Sanderson, Samuel
Subjects
Advisors
Date of Issue
2014
Date
Publisher
ASM International and the Minerals, Metals & Materials (TMS)
Language
Abstract
A comprehensive set of processing-microstructure relationships is presented for friction stir welded oxide dispersion strengthened MA956 steel. Eight rotational speed/traverse speed combinations were used to produce friction stir welds on MA956 plates using a polycrystalline cubic boron nitride tool. Weld conditions with high thermal input produced defect-free, full- penetration welds. Electron backscatter diffraction results showed a significant increase in grain size, a persistent body centered cubic torsional texture in the stir zone, and a sharp transition in grain size across the thermo-mechanically affected zone sensitive to weld parameters. Micro- indentation showed an asymmetric reduction in hardness across a transverse section of the weld. This gradient in hardness was greatly increased with higher heat inputs. The decrease in hardness after welding correlates directly with the increase in grain size and may be explained with a Hall–Petch type relationship.
Type
Article
Description
The article of record as published may be found at http://dx.doi.org/10.1007/s40553-014-0033-6
Series/Report No
Department
Mechanical and Astronautical Engineering
Organization
Naval Postgraduate School (U.S.)
Identifiers
NPS Report Number
Sponsors
U.S. Department of Energy
Funder
Contract DE-AC51-07NA27344
Format
13 p.
Citation
B.W. Baker, et al, "Processing-microstructure relationships in friction stir welding of MA956 oxide dispersion strengthened steel," Metallurgical and Materials Transactions E, v.1E, (December 2014), pp. 318-330.
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.
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