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Development of Microstructure in Mechanically Alloyed NiAl

Published online by Cambridge University Press:  22 February 2011

Sung G. Pyo  and
Nack J. Kim
Sung G. Pyo
Affiliation:
Center for Advanced Aerospace Materials and Dept. of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 790–784 KOREA
Nack J. Kim
Affiliation:
Center for Advanced Aerospace Materials and Dept. of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 790–784 KOREA
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Abstract

NiAl intermetallic powder has been synthesized by mechanical alloying of elemental powders in an attritor mill using controlled atmosphere. The mechanically alloyed (MA) powders were consolidated by vacuum hot pressing (VHP), resulting in a material which was fully dense. Analytical transmission electron microscopy has been used to understand the development of microstructure with processing. The dispersoid particles present are mostly A12O3 with small amount of A1N. It has been shown that morphology of the dispersoid particles are not uniform and the larger dispersoid particles are located mostly along the grain boundaries with the dispersoid-free zones near them. Coarsening behavior of the dispersoid particles is different depending on their locations, i.e., within the grain or along the grain boundaries. The accelerated coarsening of dispersoids along the grain boundaries occurs concurrently with that of the grains and the formation of dispersoid-free zones (DFZs) are observed along the grain boundaries. It is suggested that this abnormal dispersoid coarsening and the formation of DFZ are due to the coupled migration of dispersoids and grain boundaries.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 364: Symposium L – High-Temperature Ordered Intermetallic Alloys–VI , 1994 , 585
Copyright
Copyright © Materials Research Society 1995

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