Thermal stability of lamellar structure of PST crystal and lamellar boundary design for creep resistant TiAl alloy
Thermal stability of lamellar structure of PST crystal and lamellar boundary design for creep resistant TiAl alloy
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PST晶体层状结构的热稳定性及抗蠕变TiAl合金层状边界设计
DOI：
10.1007/bf03027044
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发表时间：
2003
影响因子：
3.5
通讯作者：
K. Maruyama
中科院分区：
文献类型：
--
作者：
H. Y. Kim;J. Matsuda;K. Maruyama
片层结构的稳定性对TiAl合金的蠕变抗力至关重要，但高温下片层结构的退化是不可避免的。Ti-48 mol.%的PST晶体片层结构的退化在高温暴露（退火和蠕变测试）期间研究Al，以检查如何制造具有高蠕变变形阻力的稳定层状结构。由于γ层片的六种取向变体独立于相邻的层片成核，因此在层片形成的初始阶段最常观察到假孪晶和120°旋转断层边界。在片层结构演化过程中，高能量（假孪晶和120°旋转断层）晶界的优先去除导致在片层演化的后期极有可能出现真孪晶晶界。在蠕变过程中，片层间距的粗化和片层的球化是主要的劣化过程，而这两种劣化过程都是由片层边界的迁移引起的。TiAl合金的片层组织包含四种类型的片层边界。四种边界的稳定性依次为：γ/α2>真孪晶>假孪晶>或=120°旋转断层边界。γ/α 2界面的稳定性最高（迁移率最低），高密度的γ/α 2界面有利于形成具有良好抗蠕变性能的稳定片层组织。通过对PST晶体在α+γ两相区进行热处理，获得了具有高密度γ/α 2晶界的材料。通过对由该材料制成的硬取向PST晶体的蠕变试验，证明了该材料优异的蠕变性能。
The stability of lamellar structure is crucial for the creep resistance of TiAl alloys, but degradation of the lamellar structure is unavoidable at high temperatures. The degradation of the lamellar structure in PST crystals of Ti-48mol.%Al was studied during high temperature exposure (annealing and creep testing) to examine how to make a stable lamellar structure with high creep deformation resistance. Since the six orientation variants of γ lamellae are nucleated independently of the adjoining lamellae, pseudo twin and 120° rotational fault boundaries are most frequently observed at the initial stage of lamellar formation. The preferential removal of high energy (pseudo twin and 120° rotational fault) boundaries during the evolution of lamellar structure results in the highly probable appearance of a true twin boundary at a later stage of lamellar evolution. The coarsening of lamellar spacing and the spheroidization of the lamellae are the major degradation events occurring during creep deformation, and the migration of the lamellar boundaries brings both of them about. The lamellar structures of TiAl alloy contain four types of lamellar boundaries. The stability of the four types of boundaries decreases in the following order: γ/α2> true twin > pseudo twin > or=120° rotational fault boundaries. The γ/α2boundary has the highest stability (lowest mobility), and the high density of γ/α2boundaries is proposed to make a stable lamellar structure with good creep resistance. A material having the high density of γ/α2boundaries was produced through the heat treatment of a PST crystal in the α+γ two-phase regime. The excellent creep properties of the material were proven through creep tests of hard oriented PST crystals made of the material.
影响因子：
9.4
作者：
H. Y. Kim;K. Maruyama
通讯作者：
H. Y. Kim;K. Maruyama
DOI：
10.1080/01418619208201574
发表时间：
1992-10-01
期刊：
PHILOSOPHICAL MAGAZINE A-PHYSICS OF CONDENSED MATTER STRUCTURE DEFECTS AND MECHANICAL PROPERTIES
影响因子：
--
作者：
INUI, H;OH, MH;YAMAGUCHI, M
通讯作者：
YAMAGUCHI, M
DOI：
10.1080/01418610008216473
发表时间：
2000-10
期刊：
Philosophical Magazine A
影响因子：
--
作者：
G. Wegmann;K. Maruyama
通讯作者：
G. Wegmann;K. Maruyama