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Mechanochemically synthesized NbC cermets: Part II. Mechanical properties

Published online by Cambridge University Press:  31 January 2011

B. R. Murphy
Affiliation:
Department of Metallurgical and Materials Engineering, Michigan Technological University, Houghton, Michigan 49931
T. H. Courtney
Affiliation:
Department of Metallurgical and Materials Engineering, Michigan Technological University, Houghton, Michigan 49931
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Abstract

The mechanical behavior of mechanochemically synthesized NbC cermets was investigated. Material hardnesses range from a high of 19.6 GPa for as-synthesized cermets containing about 4 vol% of Fe to a low of about 4 GPa for heat-treated cermets containing about 34 vol% Cu. Higher hardness generally correlates with lower fracture toughness (about 2 MPa m1/2 for cermets containing the highest percentage of NbC) and vice versa. Highest fracture toughness (about 7.5 MPa m1/2) is found in NbC–18 vol% Fe cermets heat treated extensively following consolidation. Abnormally low fracture toughnesses are found in high-Cu-content cermets in which Cu segregation takes place during heat treatment. Current models of ceramic toughening can be applied to describe the fracture behavior of NbC–Fe cermets.

Type
Articles
Copyright
Copyright © Materials Research Society 1999

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References

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