Importance of microstructural stability to creep strength of fully lamellar TiAl alloys

被引：0

作者：

Yamamoto, R ^{[1
]}

Mizoguchi, K ^{[1
]}

Wegmann, G ^{[1
]}

Maruyama, K ^{[1
]}

机构：

[1] Mitsubishi Heavy Ind Co Ltd, Hiroshima, Japan

来源：

GAMMA TITANIUM ALUMINIDES 1999 | 1999年

关键词：

D O I：

暂无

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

The objective of the present paper is to discuss how to improve creep strength of fully lamellar TiAl alloys by means of the optimization of their microstructure. Grain size, volume fraction of constituent phases and lamellar spacing are the major variables to be considered in microstructural design of the TiAl alloys. Among these variables, refinement of lamellar spacing is the most effective way to improve their creep strength. However, fine lamellar microstructure does not give the best creep strength at low stress. Special attention is paid to this loss of creep strength of fine lamellar microstructure at low stress. High temperature creep of a binary Ti-42mol%Al alloy with fully lamellar structure was studied. Specimens having three different lamellar microstructures, 0.1 mu m, 0.25 mu m and 1.5 mu m lamellar spacing, were used to examine effects of lamellar spacing on their creep behavior. Minimum creep rate is attained by the dynamic balance between the deceleration of creep rate in the primary creep stage and the acceleration in the tertiary creep stage. Strain hardening is the cause of the deceleration, and more significant in the fine lamellar specimen. Several types of microstructural degradation take place during creep; discontinuous coarsening of lamellar microstructure

引用

页码：641 / 652

页数：12

共 27 条

[1]

BARRETT CR, 1967, T METALL SOC AIME, V239, P170

[2] MODELING CREEP DEFORMATION OF A 2-PHASE TIAL/TI3AL ALLOY WITH A LAMELLAR MICROSTRUCTURE [J].