In situ TEM study of the effect of M/A films at grain boundaries on crack propagation in an ultra-fine acicular ferrite pipeline steel

被引：189

作者：

Zhong, Y ^{[1
]}

Xiao, F

Zhang, JW

Shan, YY

Wang, W

Yang, K

机构：

[1] Chinese Acad Sci, Met Res Inst, Shenyang 110016, Peoples R China

[2] Yanshan Univ, Coll Mat Sci & Engn, Qinhuangdao 066004, Peoples R China

来源：

ACTA MATERIALIA | 2006年 / 54卷 / 02期

关键词：

in situ TEM; fatigue crack growth; grain boundary structure; crack closure; pipeline steels;

D O I：

10.1016/j.actamat.2005.09.015

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

Microstructural refinement of structural materials generally improves their tensile properties but deteriorates their fatigue properties. However, pipeline steels with ultra-fine acicular ferrite (UFAF) possess not only high strength and toughness, but also a low fatigue-crack-growth rate (FCGR) and long fatigue-propagation life. In this paper, the micro-fracture mechanisms of an UFAF pipeline steel are investigated by in situ tensile testing in a transmission electron microscope. The results indicate that a grain-boundary-film structure composed of martensite/austenite could significantly influence the crack propagating behavior in the UFAF steel, consequently lowering the FCGR by enhancing roughness-induced crack closure during cyclic loading. (c) 2005 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

引用

页码：435 / 443

页数：9