Microstructure and Low-Cycle Fatigue of a Friction-Stir-Welded 6061 Aluminum Alloy

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	Microstructure and Low-Cycle Fatigue of a Friction-Stir-Welded 6061 Aluminum Alloy
	A. H. Feng; D. L. Chen; Z. Y. Ma
	2010
发表期刊	Metallurgical and Materials Transactions a-Physical Metallurgy and Materials Science
ISSN	1073-5623
卷号	41A 期号:10 页码:2626-2641
摘要	Strain-controlled low-cycle fatigue (LCF) tests and microstructural evaluation were performed on a friction-stir-welded 6061Al-T651 alloy with varying welding parameters. Friction stir welding (FSW) resulted in fine recrystallized grains with uniformly distributed dispersoids and dissolution of primary strengthening precipitates beta aEuro(3) in the nugget zone (NZ). Two low-hardness zones (LHZs) appeared in the heat-affected zone (HAZ) adjacent to the border between the thermomechanically-affected zone (TMAZ) and HAZ, with the width decreasing with increasing welding speed. No obvious effect of the rotational rate on the LHZs was observed. Cyclic hardening of the friction-stir-welded joints was appreciably stronger than that of base metal (BM), and it also exhibited a two-stage character where cyclic hardening of the friction-stir-welded 6061Al-T651 alloy at higher strain amplitudes was initially stronger followed by an almost linear increase of cyclic stress amplitudes on the semilog scale. Fatigue life, cyclic yield strength, cyclic strain hardening exponent, and cyclic strength coefficient all increased with increasing welding speed, but were nearly independent of the rotational rate. Most friction-stir-welded joints failed along the LHZs and exhibited a shear fracture mode. Fatigue crack initiation was observed to occur from the specimen surface, and crack propagation was mainly characterized by the characteristic fatigue striations. Some distinctive tiremark patterns arising from the interaction between the hard dispersoids/inclusions and the relatively soft matrix in the LHZ under cyclic loading were observed to be present in-between the fatigue striations.
部门归属	[feng, a. h.; chen, d. l.] ryerson univ, dept mech & ind engn, toronto, on m5b 2k3, canada. [ma, z. y.] chinese acad sci, shenyang natl lab mat sci, inst met res, shenyang 110016, peoples r china.;feng, ah (reprint author), harbin inst technol, sch mat sci & engn, harbin 150001, peoples r china;dchen@ryerson.ca
关键词	Mg-si Alloys Mechanical-properties Al-alloys Precipitation Sequence Dislocation Density Welding Parameters Tensile Properties Crystal-structure Magnesium Alloy Beta''-phase
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WOS记录号	WOS:000281323900021
引用统计	被引频次：85[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://ir.imr.ac.cn/handle/321006/31094
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	A. H. Feng,D. L. Chen,Z. Y. Ma. Microstructure and Low-Cycle Fatigue of a Friction-Stir-Welded 6061 Aluminum Alloy[J]. Metallurgical and Materials Transactions a-Physical Metallurgy and Materials Science,2010,41A(10):2626-2641.
APA	A. H. Feng,D. L. Chen,&Z. Y. Ma.(2010).Microstructure and Low-Cycle Fatigue of a Friction-Stir-Welded 6061 Aluminum Alloy.Metallurgical and Materials Transactions a-Physical Metallurgy and Materials Science,41A(10),2626-2641.
MLA	A. H. Feng,et al."Microstructure and Low-Cycle Fatigue of a Friction-Stir-Welded 6061 Aluminum Alloy".Metallurgical and Materials Transactions a-Physical Metallurgy and Materials Science 41A.10(2010):2626-2641.