Publication:
The effects of isothermal deformation and annealing on the microstructure of nickel-aluminum-bronze propeller material

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Authors
Nabach, William A.
Subjects
Friction stir processing
Nickel-aluminum-bronze
NAB
Isothermal deformation
Annealing
Optical microscopy
Scanning electron microscopy
Naval propellers
Shear deformation
Surface treament
Channel die compression
Lamellar tearing
Grain growth
Thermomechanically-affected zone
Homogenization of microstructure
Advisors
McNelley, Terry R.
Date of Issue
2003-06
Date
June 2003
Publisher
Monterey, California. Naval Postgraduate School
Language
Abstract
This thesis is a study of annealing and isothermal deformation characteristics of cast Nickel-Aluminum Bronze (NAB) in relation to Friction Stir Processing (FSP) of this material. Cast NAB is widely utilized by the U.S. Navy in the production of propellers for surface vessel and submarines. FSP is a novel method of deformation processing that is conducted by use of a rotating tool that is forced onto the surface of a material under load such that sliding and sticking friction result in a combination of frictional heating and adiabatic heating due to plastic deformation. A stirring effect results in the formation of a zone of severe shear deformation and local temperatures approaching 90% of the melting temperature. FSP results in local homogenization of the cast microstructure and conversion of it to a wrought condition in the absence of macroscopic shape change, but also in steep strain, strain rate and temperature gradients. In this thesis microstructures achieved through controlled isothermal deformation and annealing processes are recorded and analyzed. Studies of warm rolling, channel die compression and various annealing schedules were completed.
Type
Thesis
Description
Series/Report No
Department
Mechanical Engineering
Organization
Naval Postgraduate School (U.S.)
Identifiers
NPS Report Number
Sponsors
Funder
Format
xvi, 45 p. : (chiefly col.)
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
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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