Creep effects on crack growth in a Mo-Si-B alloy

被引：25

作者：

Alur, A. P.

Chollacoop, N.

Kumar, K. S.

机构：

[1] Brown Univ, Div Engn, Providence, RI 02912 USA

[2] Natl Met & Mat Techol Ctr, Pathum Thani 12120, Thailand

来源：

ACTA MATERIALIA | 2007年 / 55卷 / 03期

基金：

美国国家科学基金会;

关键词：

refractory alloy; high-temperature deformation; fatigue; creep; recrystallization;

D O I：

10.1016/j.actamat.2006.09.028

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

Crack growth behavior during monotonic and cyclic loading at elevated temperature is affected by creep and/or by environment and, therefore, high-temperature toughness and fatigue response can be temperature and loading-rate dependent. This paper reports on the effect of loading rate on fracture toughness at high temperatures for a two-phase Nlo-Si-B alloy; the observed response is understood by examining the interaction of the advancing crack with the microstructure, and the evolution of microstructure ahead of the crack tip as a consequence of the crack-tip field. Parallel studies were also performed under cyclic loading conditions by subjecting compact tension specimens to sinusoidal and trapezoidal loading waveforms. In certain cases, the microstructure ahead of the crack tip revealed several instabilities (recrystallization, grain growth and creep cavitation). Finite element analysis revealed strain localization 'pockets' ahead of the crack tip, which are thought to provide the driving force for the observed microstructural instabilities. (c) 2006 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

引用

页码：961 / 974

页数：14

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