The effects of isothermal deformation and annealing on the microstructure of nickel-aluminum-bronze in relation to the friction stir process
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Authors
Vazquez, Brian K.
Subjects
Friction stir processing
Nickel-aluminum bronze
NAB
Isothermal deformation
Annealing
Optical microscopy
Naval propellers
Surface treatment
Thermomechanically-affected zone
Shear deformation
Lamellar tearing
Grain growth
Homogenization of microstructure
Nickel-aluminum bronze
NAB
Isothermal deformation
Annealing
Optical microscopy
Naval propellers
Surface treatment
Thermomechanically-affected zone
Shear deformation
Lamellar tearing
Grain growth
Homogenization of microstructure
Advisors
McNelley, Terry R.
Date of Issue
2003-12
Date
December 2003
Publisher
Monterey, California. Naval Postgraduate School
Language
Abstract
The FSP of Nickel Aluminum Bronze is a novel approach to enhance the microstructural properties of the material through a shear deformation process. This thesis examines the effect on microstructure of isothermal annealing and quenching of as-cast Nickel Aluminum Bronze and, furthermore, reports on investigation of the effects of isothermal hot rolling on microstructure of this material. Quantitative analysis of the microstructure constituents shows that heating to about 800oC results in the formation of beta by reversion of the eutectoid constituent alpha + kappaiii. Further heating in the range of 800- 1000oC results in an approximately linear decrease in the volume fraction of primary alpha and a corresponding increase in the volume fraction of beta transformation products. Isothermal rolling of NAB over this same temperature interval results in deformation of both phases and an elongated, banded distribution of alpha and beta transformation products in the middle of this interval. This suggests that local peak temperature in the stir zone of material that has been subjected to FSP may be estimated by microstructure analysis. The yield and ultimate strengths of NAB are increased and ductility is also increased when rolled material is compared to as-cast NAB. However, strength and hardness appear to be independent of prior rolling temperature.
Type
Thesis
Description
Series/Report No
Department
Mechanical and Astronautical Engineering
Organization
Naval Postgraduate School (U.S.)
Identifiers
NPS Report Number
Sponsors
Funder
Format
xvi, 61 p. : ill. (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.