Solidification kinetics and phase formation of undercooled eutectic Ni-Nb melts

被引：82

作者：

Leonhardt, M ^{[1
]}

Löser, W ^{[1
]}

Lindenkreuz, HG ^{[1
]}

机构：

[1] Inst Festkorper & Werkstofforsch Dresden, D-01171 Dresden, Germany

来源：

ACTA MATERIALIA | 1999年 / 47卷 / 10期

关键词：

rapid solidification; nickel alloys; metallic glasses; phase transformations;

D O I：

10.1016/S1359-6454(99)00167-6

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

The non-equilibrium solidification behaviour of undercooled eutectic Ni84Nb16 and Ni59.5Nb40.5 melts has been analysed by in situ observation of recalescence events during electromagnetic levitation of undercooled melts. Levitated drops of controlled undercooling were quenched onto chill substrates and subjected to phase and microstructure analysis. For Ni84Nb16 a maximum melt undercooling of 276 K has been achieved. A transition from coupled eutectic to primary supersaturated alpha-Ni dendrite growth was revealed beyond a critical undercooling of 30 K. Beyond 110 K the primary Ni3Nb phase occurred for substrate quenching. The undercooling of Ni59.5Nb40.5 melt was limited to 135 K. Bulk amorphous samples up to 2 mm thick have been prepared by quenching of undercooled Ni59.5Nb40.5 melts. On slow cooling the metastable phases decompose into an anomalous eutectic microstructure. (C) 1999 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved.

引用

页码：2961 / 2968

页数：8

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