Microstructural transformations and mechanical properties of cast NiAl bronze: Effects of fusion welding and friction stir processing

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Authors
Fuller, M. D.
Swaminathan, S.
Zhilyaev, A. P.
McNelley, T. R.
Subjects
NiAl bronze
Transformations
Welding
Friction stir processing
Microstructure-mechanical-property relationships
Advisors
Date of Issue
2007
Date
Publisher
Elsevier
Language
Abstract
A plate of as-cast NiAl bronze (NAB) material was sectioned from a large casting. A six-pass fusion weld overlay was placed in a machined groove; a portion of the weld reinforcement was removed by milling and a single friction stir processing (FSP) pass was conducted in a direction transverse to the axis of and over the weld overlay. A procedure was developed for machining of miniature tensile samples and the distributions of strength and ductility were evaluated for the fusion weld metal; for the stir zone (SZ) produced by the friction stir processing; and for a region wherein friction stir processing had taken place over the fusion weld. A region of low ductility in the heat affected zone (HAZ) of the fusion weld and in the thermomechanically affected zone (TMAZ) of friction stir processed material was attributed to partial reversion of an equilibrium lamellar eutectoid constituent upon local heating above ∼800 ◦C and formation of non-equilibrium transformation products upon subsequent cooling. The adverse effect on ductility is worse in the heat affected zone of the fusion weld than in the thermomechanically affected zone of friction stir processing due to the lower heat input of the latter process. The implications of this work to engineering applications of friction stir processing are discussed.
Type
Article
Description
Series/Report No
Department
Department of Mechanical and Astronautical Engineerng
Organization
Naval Postgraduate School
Identifiers
NPS Report Number
Sponsors
Funder
Format
Citation
Materials Science and Engineering A, v.463, 2007, pp. 128-137
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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