日本金属学会誌

J. Japan Inst. Metals, Vol. 63, No. 9 (1999),
pp. 1161-1164

Pulsed Current Sintering of Mechanically Alloyed Ni-Ti Powder

Keizo Kobayashi, Akihiro Matsumoto, Kimihiro Ozaki,Akira Sugiyama and Toshiyuki Nishio

Materials Processing Department National Industrial Research Institute of Nagoya AIST, MITI, Nagoya 462-8510

Abstract:

In order to fabricate the compacts with complicated shape, Ni-Ti powders were synthesized by mechanical alloying(MA) and consolidated by pulsed current sintering.
Ni-50 at%Ti powders were synthesized by MA of pure elemental Ni and Ti powders using a planetary ball milling for 180 ks, 360 ks and 540 ks. The X-ray diffraction profile of the obtained MA powders contained a broad peak. MA powders milled for 180 ks and 360 ks consisted of fine Ni and Ti grains and melted at about 1150 K by self-propagating high-temperature synthesis(SHS) during pulsed current sintering. The MA powder milled for 540 ks contained a large amount of Fe. This is because NiTi phase was produced by SHS during the MA process.

The addition of 2 at%B to the starting powders of the MA was prevented a SHS reaction during pulsed current sintering. Ni-49 at%Ti-2 at%B powders synthesized by MA were consolidated to compacts with complicated shapes by pulsed current sintering. The obtained compacts consisted of NiTi, Ti2Ni, Ni3Ti and TiB2 phases. The result of differential scanning calorimetry measurement for the compacts heat-treated at 673 K for 3.6 ks suggested that those possessed shape memory effects.


(Received April 26, 1999; In Final Form August 23, 1999)

Keywords:

mechanical alloying, pulsed current sintering, NiTi, boron, combustion synthesis reaction


PDF(Free)PDF (Free)     Table of ContentsTable of Contents

Please do not copy without permission.