Extremely-low-cycle fatigue behaviors of Cu and Cu-Al alloys: Damage mechanisms and life prediction

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	Extremely-low-cycle fatigue behaviors of Cu and Cu-Al alloys: Damage mechanisms and life prediction
	R.; Zhang Liu, Z. J.; Zhang, P.; Zhang, Z. F.
	2015
发表期刊	Acta Materialia
ISSN	1359-6454
卷号	83 页码:341-356
摘要	The extremely-low-cycle fatigue (ELCF) behaviors of pure Cu and Cu-Al alloys are comprehensively studied following the cyclic push pull loading tests with extremely high strain amplitudes (up to +/- 9.5%). Compared with the common low-cycle fatigue (LCF) region, several unique features in the ELCF regime can be noticed, including the deviations of fatigue life from the Coffin-Manson law, the non-negligible proportion occupied by the cyclic hardening stage of the whole fatigue life, special microstructures formed by cyclic loading containing deformation twins, shear bands and ultra-fine grains and the transformation of fatigue cracking modes. All these characteristics indicate the existence of special interior fatigue damage mechanisms of ELCF. To help discover the new damage mechanisms under ELCF, a model of fatigue life prediction with a hysteresis energy-based criterion is proposed. Based on the analysis of the experimental and modeling results, two intrinsic factors determining the ELCF properties were concluded: the capacity of ELCF damage, and the defusing and dispersion ability of the external mechanical work. The former can be evaluated by a parameter of the model called the intrinsic fatigue toughness W-0, which is related to the microstructure evolution condition, the cyclic hardening ability, the deformation homogeneity and possibly the static toughness. The latter can be represented by the damage transition exponent beta, which can be enhanced by improving the planarity, reversibility and uniformity of plastic deformation, reflecting the decline in the degree of surface damage and the dispersion of fatigue cracks. For Cu-Al alloys with increasing Al content, cooperation between an increasing damage capacity and a decreasing damage accumulation rate leads to a comprehensive improvement in the ELCF properties. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
部门归属	[liu, r. ; zhang, z. j. ; zhang, p. ; zhang, z. f.] chinese acad sci, inst met res, shenyang natl lab mat sci, shenyang 110016, peoples r china. ; zhang, zf (reprint author), chinese acad sci, inst met res, shenyang natl lab mat sci, shenyang 110016, peoples r china. ; zhfzhang@imr.ac.cn
关键词	Extremely-low-cycle Fatigue Cyclic Hardening Fatigue Crack Hysteresis Energy Damage Mechanism Stacking-fault Energy Ductile Crack Initiation Ultrafine-grained Cu Microstructural Evolution Hysteresis Energy Steel Strain Deformation Assessments Transition
URL	查看原文
文献类型	期刊论文
条目标识符	http://ir.imr.ac.cn/handle/321006/73867
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	R.,Zhang Liu, Z. J.,Zhang, P.,et al. Extremely-low-cycle fatigue behaviors of Cu and Cu-Al alloys: Damage mechanisms and life prediction[J]. Acta Materialia,2015,83:341-356.
APA	R.,Zhang Liu, Z. J.,Zhang, P.,&Zhang, Z. F..(2015).Extremely-low-cycle fatigue behaviors of Cu and Cu-Al alloys: Damage mechanisms and life prediction.Acta Materialia,83,341-356.
MLA	R.,et al."Extremely-low-cycle fatigue behaviors of Cu and Cu-Al alloys: Damage mechanisms and life prediction".Acta Materialia 83(2015):341-356.