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Strain-rate sensitivity of hardness of nanocrystalline Ni75at.%Al25at.% alloy film

Published online by Cambridge University Press:  31 January 2011

A.H.W. Ngan
Affiliation:
Department of Mechanical Engineering, University of Hong Kong, Pokfulam Road, Hong Kong, People's Republic of China
J.B. Pethica
Affiliation:
Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom
H.P. Ng
Affiliation:
Laboratoire des Matériaux et du Génie Physique, Ecole Nationale Supérieure de Physique de Grenoble-Institut National Polytechnique de Grenoble (ENSPG-INPG), UM 5628, BP 46, 38402, St. Martin d'Hères, France
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Abstract

Room-temperature indentation experiments carried out on nanocrystalline Ni75at.%Al25at.% alloy films with a range of grain sizes revealed that the strain-rate sensitivity of hardness is nearly zero and that the hardness increases as grain size decreases. The strain-rate insensitivity of hardness indicates that the room-temperature strength of these alloy films is dominated by an athermal, strain-rate-insensitive component. The hardness of the films was found to be in the range of 2.4 to 3.3 GPa, depending on grain size.

Type
Articles
Copyright
Copyright © Materials Research Society 2003

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