Microstructure evolution and microstructure - property relationships in friction stir processing of NiAl bronze
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Authors
McNelley, T.R.
Oh-Ishi, K.
Zhilyaev, A.P.
Subjects
Friction stir processing
NiAl bronze
As-cast
Porosity
Grain refinement
Ductility
NiAl bronze
As-cast
Porosity
Grain refinement
Ductility
Advisors
Date of Issue
2007
Date
Publisher
Trans Tech Publications
Language
Abstract
Abstract. Friction stir processing (FSP) has been employed for localized modification and control
of microstructures in NiAl bronze materials, which are widely utilized for marine components. The
thermomechanical cycle of FSP results in homogenization and refinement and the conversion of
microstructures from a cast to a wrought condition within stir zones in the material. However, the
direct measurement of stir zone temperatures, strains, strain rates and cooling rates is difficult
due to steep gradients and transients in these quantities, and this is an impediment in the
assessment of FSP-induced microstructures and properties. Quantitative microstructure analyses
following FSP of cast NiAl bronze materials have been used to develop estimates of stir zone
thermomechanical cycles. The estimation procedures will be reviewed and the microstructure-based
estimates will be compared to results from computational models and embedded thermocouples
measurements. Stir zone microstructures comprise a mixture of primary α grains and transformation
products of the β that formed during processing. Recrystallization in the primary α occurred due to
particle-stimulated nucleation in this low stacking fault energy material. Factors that influence
the distribution of strength and ductility in the stir zone appear to include the mixture of
microstructure constituents and gradients in microstructure due to gradients in processing
conditions.
Type
Article
Description
The article of record as published may be found at http://dx.doi.org/10.4028/www.scieintific.net/MSF.539-543.3745
Series/Report No
Department
Mechanical and Astronautical Engineering
Organization
Naval Postgraduate School (U.S.)
Identifiers
NPS Report Number
Sponsors
Defense Advanced Research Projects Agency (DARPA)
Funder
Format
6 p.
Citation
T.R. McNelley, K. Oh-Ishi, A.P. Zhilyaev, "Microstructure evolution and Microstructure - property relationships in friction stir processing of NiAl bronze," Material Science Forum, v.539-543, (2007) pp. 3745-3750.
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.