A revision of the Fe-Ni phase diagram at low temperatures (<400 °C)
A revision of the Fe-Ni phase diagram at low temperatures (<400 °C)
复制标题
DOI：
10.1007/bf02665999
复制
发表时间：
1996-12
期刊：
影响因子：
--
通讯作者：
Cheol‐Woong Yang;David B. Williams;J. Goldstein
中科院分区：
文献类型：
--
作者：
Cheol‐Woong Yang;David B. Williams;J. Goldstein
利用高分辨分析电子显微镜技术对陨石中的铁镍区进行了实验研究，获得了低温铁镍相图。该相图与现有的基于陨石结构观测的实验相图不同，但与现有的理论相图一致，因为α/Ni_3Fe平衡是在低温下发现的。α相含有3.6重量%的Ni与γ′（Ni 3Fe）相处于局部平衡，其中γ′（Ni 3Fe）相含量为65.5wt.%，Ni，而γ“（FeNi）相作为亚稳相存在。新的相图包括在约400 °C下的单析反应（γ1→ α + γ2，其中γ 1是顺磁性fcc奥氏体，α是bcc铁素体，γ 2是铁磁性fcc奥氏体），在约345 °C下的共析反应（γ2→ α + γ′），以及在低温下与旋节区相关的可熔性间隙。溶解性间隙位于9.0和51.5wt. %的Ni。新的低温Fe-Ni相图与陨石金属区观察到的所有相一致。
The low-temperature Fe-Ni phase diagram was assessed experimentally by investigating Fe-Ni regions of meteorites using high resolution analytical electron microscopy techniques. The present phase diagram differs from the available experimental phase diagram based on observations of meteorite structure, but it is consistent with the available theoretical diagram in that α/Ni3Fe equilibrium was found at low temperatures. The a phase containing 3.6 wt.% Ni is in local equilibrium with the γ′ (Ni3Fe) phase containing 65.5 wt.% Ni, while the γ′' (FeNi) phase is present as a metastable phase. The new phase diagram incorporates a monotectoid reaction (γ1→ α + γ2, where (γ1is a paramagnetic fcc austenite, a is a bcc ferrite, and γ2is a ferromagnetic fcc austenite) at about 400 °C, a eutectoid reaction (γ2→ α + γ′) at about 345 °C, and a miscibility gap associated with a spinodal region at low temperatures. The miscibility gap is located between 9.0 and 51.5 wt. % Ni at ∼200 °C. The new low-temperature Fe-Ni phase diagram is consistent with all the phases observed in the metallic regions of meteorites.