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Title: The effect of microstructural evolution on superplasticity in Ni{sub 3}Si(V,Mo)

Abstract

To further the understanding of superplasticity in intermetallics, this paper presents results of experimental investigations on an intermetallic alloy based on nickel silicide. Specifically, the evolution of the microstructure and its influence on superplastic performance is discussed. In the duplex microstructure, one phase showed grain growth, and the other, grain refinement. Cavitation occurred at interphase boundaries and final failure was by interlinkage of these cavities. Annealing the material improved the homogeneity of the microstructure. The annealed material showed improved strain rate sensitivity values and enhanced superplasticity. Microstructural features and ductility were also influenced by changing the orientation of the tensile axis. Though a transverse orientation showed more cavitation than longitudinal, it yielded greater elongation. An increased resistance to cavity coalescence in the transverse direction played a role in the enhanced ductility.

Authors:
 [1];  [2]
+ Show Author Affiliations
  1. Lawrence Livermore National Lab., CA (United States)
  2. California Univ., Davis, CA (United States). Dept. of Mechanical, Aeronautical and Materials Engineering
Publication Date:
Research Org.:
Lawrence Livermore National Lab., CA (United States)
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
10190595
Report Number(s):
UCRL-JC-112108; CONF-9211268-1
ON: DE93041320
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Conference
Resource Relation:
Conference: Advances in superplasticity and superplastic forming,Chicago, IL (United States),1-5 Nov 1992; Other Information: PBD: Oct 1992
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; NICKEL SILICIDES; PLASTICITY; MOLYBDENUM ALLOYS; VANADIUM ALLOYS; INTERMETALLIC COMPOUNDS; MICROSTRUCTURE; CAVITATION; ANNEALING; 360203; 360103; MECHANICAL PROPERTIES

Citation Formats

Stoner, S.L., and Mukherjee, A.K.. The effect of microstructural evolution on superplasticity in Ni{sub 3}Si(V,Mo). United States: N. p., 1992. Web.
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Stoner, S.L., & Mukherjee, A.K.. The effect of microstructural evolution on superplasticity in Ni{sub 3}Si(V,Mo). United States.
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Stoner, S.L., and Mukherjee, A.K.. Thu . "The effect of microstructural evolution on superplasticity in Ni{sub 3}Si(V,Mo)". United States. doi:. https://www.osti.gov/servlets/purl/10190595.
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@article{osti_10190595,
title = {The effect of microstructural evolution on superplasticity in Ni{sub 3}Si(V,Mo)},
author = {Stoner, S.L. and Mukherjee, A.K.},
abstractNote = {To further the understanding of superplasticity in intermetallics, this paper presents results of experimental investigations on an intermetallic alloy based on nickel silicide. Specifically, the evolution of the microstructure and its influence on superplastic performance is discussed. In the duplex microstructure, one phase showed grain growth, and the other, grain refinement. Cavitation occurred at interphase boundaries and final failure was by interlinkage of these cavities. Annealing the material improved the homogeneity of the microstructure. The annealed material showed improved strain rate sensitivity values and enhanced superplasticity. Microstructural features and ductility were also influenced by changing the orientation of the tensile axis. Though a transverse orientation showed more cavitation than longitudinal, it yielded greater elongation. An increased resistance to cavity coalescence in the transverse direction played a role in the enhanced ductility.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Oct 01 00:00:00 EDT 1992},
month = {Thu Oct 01 00:00:00 EDT 1992}
}
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Conference:
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  • The fundamentals of superplasticity, including mechanical and microstructural characteristics are reviewed. The interest in developing intermetallic alloys for high temperature, structural applications is discussed. The superplastic properties of an intermetallic alloy based on nickel silicide have been investigated. A duplex microstructure is shown with a third phase present as dispersions. The {beta} phase is ordered and the ({alpha}+{beta}) phase is a mixture of a solid solution phase and {beta} dispersions. The mechanical behavior of the material is presented. The maximum strain-rate sensitivity is approximately 0.5. The stress/strain curve varies with temperature, strain-rate, and orientation of the tension with respect tomore » the microstructure. Steady-state behavior is shown in Region II as well as strain hardening caused by dynamic growth of the {beta} phase. ({alpha}+{beta}) grains refine with deformation. Growth and refinement are enhanced at slower strain-rates. The nickel silicide alloy cavitates during superplasticity and shows increasing cavitation with decreasing strain-rate. The failure mechanism is intergranular and the final failure occurs by cavity coalescence. Annealing the material prior to testing produced a more uniform microstructure and improve the superplastic performance of the alloy. 43 refs.« less

  • The fundamentals of superplasticity, including mechanical and microstructural characteristics are reviewed. The interest in developing intermetallic alloys for high temperature, structural applications is discussed. The superplastic properties of an intermetallic alloy based on nickel silicide have been investigated. A duplex microstructure is shown with a third phase present as dispersions. The {beta} phase is ordered and the ({alpha}+{beta}) phase is a mixture of a solid solution phase and {beta} dispersions. The mechanical behavior of the material is presented. The maximum strain-rate sensitivity is approximately 0.5. The stress/strain curve varies with temperature, strain-rate, and orientation of the tension with respect tomore » the microstructure. Steady-state behavior is shown in Region II as well as strain hardening caused by dynamic growth of the {beta} phase. ({alpha}+{beta}) grains refine with deformation. Growth and refinement are enhanced at slower strain-rates. The nickel silicide alloy cavitates during superplasticity and shows increasing cavitation with decreasing strain-rate. The failure mechanism is intergranular and the final failure occurs by cavity coalescence. Annealing the material prior to testing produced a more uniform microstructure and improve the superplastic performance of the alloy. 43 refs.« less

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