Role of lamellar plates in creep of TiAl alloy with fully lamellar structure

被引：11

作者：

Matsuo, T ^{[1
]}

Nozaki, T ^{[1
]}

Asai, T ^{[1
]}

Takeyama, M ^{[1
]}

机构：

[1] Tokyo Inst Technol, Dept Met & Ceram Sci, Meguro Ku, Tokyo 1528552, Japan

来源：

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING | 2002年 / 329卷

基金：

日本学术振兴会;

关键词：

TiAl alloy with fully lamellar structure; transient creep; onset of accelerating creep; creep rate time curve; dynamic recrystallization; PST crystal; lamellar orientation to stress axis; interlamellar spacing of alpha(2) plate;

D O I：

10.1016/S0921-5093(01)01632-X

中图分类号：

TB3 [工程材料学];

学科分类号：

0805 ; 080502 ;

摘要：

The role of lamellar plates in near gamma Ti-48 at.% Al alloy with fully transformed lamellar structure was investigated by studying the difference in creep rate-time curve between Ti-48 at.% Al alloy and the gamma single phase Ti-50 at.% Al alloy. Creep tests were conducted at 1123 K under a low stress of 68.6 MPa. The superiority of FL specimen is derived not from decreasing the creep rate, but from retarding the onset of accelerating creep. The absence of dynamic recrystallization along grain boundaries is interpreted as causing retardation of accelerating creep. The alpha(2) lamellar plates have a more drastic effect on suppressing dynamic recrystallization than the gamma lamellar plates. Dynamic recrystallization would be fully suppressed in a Ti-Al PST crystal, because of the absence of grain boundaries. By conducting the creep tests of PST crystals with different lamellar orientations to stress axis, phi, phi dependence of creep rate was investigated. In the specimens with phi from 30 to 70degrees. creep rate is larger than that in polycrystalline FL specimen. For the specimen with phi less than 30degrees and larger than 80degrees, the creep rate becomes smaller than that of the FL specimen, and in the case of the specimens with phi near 0 or 90degrees a marked decrease in creep rate is confirmed. The correlation between interlamellar spacing and creep rate is investigated using FL specimen with four different interlamellar spacing. Decreasing the interlamellar spacing gives a short transient stage and a short accelerating stage. (C) 2002 Elsevier Science B.V. All rights reserved.

引用

页码：774 / 779

页数：6

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