Ni-25Al-15Cr多相金属间化合物的显微组织

中国有色金属学报990310

中国有色金属学报

THE CHINESE JOURNAL OF

NONFERROUS METALS

1999年　第9卷　第3期　Vol.9　No.3　1999

Ni-25Al-15Cr多相金属间化合物的显微组织

陈荣石　郭建亭　周继扬

摘　要：研究了Ni-25Al-15Cr(摩尔分数，%)多相金属间化合物合金的显微组织及热处理对其组织的影响。结果表明：1200℃24h均匀化后的冷却速度不仅影响β相中α-Cr 析出物的尺寸，且影响β相的成分及体积分数；空冷后时效，β相分解成γ′相和有序度更高的β相，炉冷后时效，β相保持稳定；并对时效过程中β相稳定性与时效前冷却速度之间的关系进行了讨论。

关键词：NiAl合金；金属间化合物；显微组织；热处理

中图分类号：TG319

文献标识码：A

Microstructure of multiphase Ni-25Al-15Cr intermetallic alloy

Chen Rongshi, Guo Jianting, Zhou Jiyang

1. Institute of Metal Research,

Chinese Academy of Sciences, Shenyang 110015, P.R.China

2. Department of Material Engineering,

Dalian University of Technology, Dalian 116024 P. R. China

Abstract: The effects of heat treatment on the microstructure of a multiphase Ni-25%Al-15%Cr (mole fraction) intermetallic alloy have been investigated. It is shown that cooling rates following homogenization affect not only the size of α-Cr in β phase but also the composition and volume fraction of β phase. The β phase may either decompose into γ′ and more strongly ordered β phase or remain stable during aging, depending on the cooling rates preceding aging. The relationships between stability of β phase and cooling rates preceding aging has also been discussed.

Key words： nickel-aluminium alloys; intermetallic compounds; microstructure; heat treatment NiAl具有熔点高、比重小、抗氧化性能好等优点而有希望取代镍基高温合金成为下一代高温结构材料；但室温塑性差，高温强度低，阻碍了它的实用化。为提高NiAl 的室温塑性，人们已尝试了多种方法：如细化晶粒、做成单晶材料、调整化学成分等［1～3］。在提高NiAl室温塑性的各种尝试中，宏合金化引入塑料第二相使其成为

βNiAl+γ(Ni固溶体)+γ′(Ni3Al)多相合金，被认为是最有希望的方法。最成功的例子为Ni-20%Al-30%Fe(摩尔分数，下同，皆略)合金，其显微组织由先共晶的βNiAl和

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