Laves Phases for High Temperatures – Structure, Stability and Constitution
Laves Phases for High Temperatures – Structure, Stability and Constitution
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DOI：
10.3139/ijmr-1998-0157
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发表时间：
1998-12
影响因子：
0.8
通讯作者：
A. Keitz;G. Sauthoff;P. Neumann
中科院分区：
文献类型：
--
作者：
A. Keitz;G. Sauthoff;P. Neumann
摘要作为过渡金属Laves相研究工作的一部分，研究了Al合金化对Laves相NbCo_2和TaFe_2相稳定性和晶体结构的影响。根据相应的三元相图，三元相可以描述为Nb（Co 1-xAlx）2和Ta（Fe 1-xAlx）2。测量了熔融温度和晶格常数。研究了Ta（Fe_（1-x）Al_x）_2与体心立方Fe-Al、D_0_3结构Fe_3Al和B_2结构FeAl的相平衡。NbCo 2的立方C15结构在1050 ~ 1350 °C温度范围内转变为六方C14结构，当Al含量高于5at.%时，NbCo 2的立方C15结构不稳定具有C15结构的Laves相的稳定性受到高价电子浓度的支持。
Abstract The effect of alloying with Al on phase stability and crystal structure of the Laves phases NbCo2 and TaFe2 was studied as part of extended work on Laves phases of transition metals. The ternary phases can be described as Nb(Co1–xAlx)2 and Ta(Fe1–xAlx)2 in view of the respective ternary phase diagrams. Melting temperatures and lattice constants have been measured. The phase equilibria between Ta(Fe1–xAlx)2 and bcc Fe–Al, Fe3Al with D03 structure and FeAl with B2 structure have been studied. The cubic C15 structure of NbCo2 transforms to the hexagonal C14 structure in the temperature range 1050 to 1350 °C and is unstable for Al contents above 5 at.% Al. The stability of Laves phases with C15 structure is favoured by a high valence electron concentration.