Micromechanism of Cleavage Fracture ofWeld Metals

doi:10.11900/0412.1961.2017.00145

	Micromechanism of Cleavage Fracture ofWeld Metals
	Chen, Jianhong 1,2; Cao, Rui 1,2
刊名	Jinshu Xuebao/Acta Metallurgica Sinica
	2017-11-11
卷号	53 期号:11 页码:1427-1444
关键词	Crystallization Fracture Fracture toughness High strength alloys High-strength low-alloy steel Nickel steel Nucleation Particle size analysis Temperature Cleavage fracture Critical events Fracture criteria Fracture process Grain-sized crack High strength low alloys Micro mechanisms Temperature regions
ISSN号	04121961
DOI	10.11900/0412.1961.2017.00145
英文摘要	Cleavage fracture is the most dangerous form of fracture. Cleavage fracture usually happens well before general yielding at low nominal fracture stress and strain. Cleavage fracture is often spurred by low temperature and determines the toughness in the lower shelf temperature region. This paper describes a new framework for the micromechanism of cleavage fracture of high strength low alloy (HSLA) steel weld metals. Cleavage fracture not only determines the impact toughness in the lower shelf but also plays a decisive role on the impact toughness in the transition temperature region. The toughness is determined by the extending length of a preceding fibrous crack which is terminated by cleavage fracture. Three non-stop successive stages, i.e. crack nucleation, propagation of a second phase particlesized crack across the particle/grain boundary, propagation of a grain-sized crack across the grain/grain boundary are explained. The "critical event" of cleavage fracture is emphasized which offers the greatest difficulty during crack formation and controls the cleavage process. The critical event indicates the weakest microstructural component and its critical size which specifies the local cleavage fracture stress sf for cleavage fracture. In toughness-study it is paramount important to reveal the critical events for various test specimens. Three criteria for crack nucleation, for preventing crack nucleus from blunting and for crack propagation are testified. An active region specified by these criteria is suggested where the combined stress and strain are sufficient to trigger the cleavage fracture. It can be used in statistical analyses. A case study, using the new framework of micromechanism for analyzing toughness of 8%Ni steel welding metals is presented to analyze the experimental results. © All right reserved.
WOS研究方向	Metallurgy & Metallurgical Engineering
语种	中文
出版者	Chinese Academy of Sciences
WOS记录号	WOS:000416301500003
内容类型	期刊论文
源URL	[http://ir.lut.edu.cn/handle/2XXMBERH/114403]
专题	材料科学与工程学院
作者单位	1.State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metal, Department of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou; 730050, China; 2.Department of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou; 730050, China
推荐引用方式 GB/T 7714	Chen, Jianhong,Cao, Rui. Micromechanism of Cleavage Fracture ofWeld Metals[J]. Jinshu Xuebao/Acta Metallurgica Sinica,2017,53(11):1427-1444.
APA	Chen, Jianhong,&Cao, Rui.(2017).Micromechanism of Cleavage Fracture ofWeld Metals.Jinshu Xuebao/Acta Metallurgica Sinica,53(11),1427-1444.
MLA	Chen, Jianhong,et al."Micromechanism of Cleavage Fracture ofWeld Metals".Jinshu Xuebao/Acta Metallurgica Sinica 53.11(2017):1427-1444.