Microstructure and Phase Stability in MoSi2-TSi2 (T=Cr, V, Nb, Ta, Ti) Pseudo-Binary Systems.
Microstructure and Phase Stability in MoSi2-TSi2 (T=Cr, V, Nb, Ta, Ti) Pseudo-Binary Systems.
复制标题
DOI：
10.2320/matertrans.42.1349
复制
发表时间：
2001-07
影响因子：
1.2
通讯作者：
F. Wei;Y. Kimura;Y. Mishima
中科院分区：
文献类型：
--
作者：
F. Wei;Y. Kimura;Y. Mishima
通过建立MoSi 2 -TSi 2 (T=Cr、V、Nb、Ta、Ti)伪二元相图，研究了MoSi 2 和Cr、V、Nb、Ta、Ti等其他类型的过渡金属二硅化物的准二元体系中二硅化钼(MoSi 2 、C1 1 b结构)相对于其他相(C40和C54相)的相稳定性。研究发现，V、Nb、Ta和Ti替代MoSi 2 中的Mo，对C40相具有较强的稳定作用，而Cr仅表现出较弱的C40结构稳定作用。还根据组成变化时三相的几何变化讨论了相稳定性。各相晶格参数的变化表明C1 1 b 、C40和C54结构的相稳定性很大程度上取决于这三种结构的等效六方原子平面的相对堆叠间距。基于相图研究的结果，本工作尝试设计C11b/C40层状微观结构，C11b、C40和C54相之间等效六方堆叠原子平面的存在使得设计相干的C11b/C40两相微观结构成为可能。假设C 11 b 和C40 相的等效原子面重合，MoSi 2 -CrSi 2 系中C 11 b 和C40 相之间具有较高的晶格共格性，其晶格失配率小于0.5%，而在其他四个体系中，失配率在1.3%至2.7%之间，在MoSi 2 -TaSi 2 和MoSi 2 -NbSi 2 中观察到层状微观结构。 MoSi 2 -CrSi 2 、MoSi 2 -VSi 2 和MoSi 2 -TiSi 2 体系中没有获得层状微观结构。
The phase stability of molybdenum disilicide (MoSi 2 , C1 1 b structure) relative to other phases, C40 and C54 phases, in the pseudo-binary systems of MoSi 2 and other types of disilicides of transition metals including Cr, V, Nb, Ta and Ti was investigated by establishing the MoSi 2 -TSi 2 (T=Cr, V, Nb, Ta, Ti) pseudo-binary phase diagrams. It was found that V, Nb, Ta and Ti which substitute for Mo in MoSi 2 strongly stabilize the C40 phase while Cr only shows a weak C40 structure-stabilizing effect. The phase stability was also discussed on the basis of geometrical change in the three phases when composition varies. Change in lattice parameter of each phase indicated that phase stability of C1 1 b , C40 and C54 structures greatly depend on the relative stacking spacing of the equivalent hexagonal atomic plane for the three structures. Based on the results of phase diagram investigation, the present work attempted to design a C11 b /C40 lamellar microstructure, Existence of the equivalent hexagonal stacking atomic plane among C1 1 b , C40 and C54 phases makes it possible to design a coherent C 11 b /C40 two-phase microstructure. Assuming the equivalent atomic planes in C 11 b and C40 phases coincide with each other, high lattice coherency between C 11 b and C40 phases is available in MoSi 2 -CrSi 2 system with a lattice misfit of less than 0.5% and in the other four systems with a misfit of 1.3 to 2.7%, A lamellar microstructure was observed in MoSi 2 -TaSi 2 and MoSi 2 -NbSi 2 systems but no lamellar microstructures were obtained in MoSi 2 -CrSi 2 , MoSi 2 -VSi 2 and MoSi 2 -TiSi 2 systems.