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On sinterability of nanostructured W produced by high-energy ball milling

Published online by Cambridge University Press:  03 March 2011

R. Malewar ,
K.S. Kumar ,
B.S. Murty ,
B. Sarma  and
S.K. Pabi
R. Malewar
Affiliation:
Defense Metallurgical Research Laboratory, Hyderabad, India
K.S. Kumar
Affiliation:
Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Kharagpur 721302, India
B.S. Murty
Affiliation:
Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Madras, Chennai 600036, India
B. Sarma
Affiliation:
Defense Metallurgical Research Laboratory, Hyderabad, India
S.K. Pabi*
Affiliation:
Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Kharagpur 721302, India
*
a) Address all correspondence to this author. e-mail: skpabi@metal.iitkgp.ernet.in
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Abstract

The present investigation reports for the first time a dramatic decrease in the sintering temperature of elemental W from the conventional temperature of ≥2500 °C to the modest temperature range of 1700–1790 °C by making the W powder nanostructured through high-energy mechanical milling (MM) prior to sintering. The crystallite size of the initial W powder charge with a particle size of 3–4 μm could be brought down to 8 nm by MM for 5 h in WC grinding media. Further milling resulted in a high level of WC contamination, which apparently was due to work hardening and the grain refinement of W. A sintered density as high as 97.4% was achieved by sintering cold, isostatically pressed nanocrystalline (8 nm) W powder at 1790 °C for 900 min. The microstructure of the sintered rods showed the presence of deformation bands, but no cracks, within a large number of W grains. The mechanical properties, when compared with the hardness and elastic modulus, of the sintered nano-W specimen were somewhat superior to those reported for the conventional sintered W.

Keywords

NanostructureSinteringW
Type
Articles
Information
Journal of Materials Research , Volume 22 , Issue 5 , May 2007 , pp. 1200 - 1206
Copyright
Copyright © Materials Research Society 2007

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