Rapid cycle-dependent softening of equal channel angularly pressed Sn-Ag-Cu alloy

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	Rapid cycle-dependent softening of equal channel angularly pressed Sn-Ag-Cu alloy
	Q. S. Zhu ; Z. G. Wang ; Q. L. Zeng ; S. D. Wu ; J. K. Shang
刊名	Journal of Materials Research
	2008
卷号	23 期号:10 页码:2630-2638
关键词	lead-free solders thermomechanical fatigue behavior joints microstructure anisotropy metals
ISSN号	0884-2914
中文摘要	Cyclic stress-strain response of an equal channel angularly pressed Sn-3.8Ag-0.7Cu alloy was investigated to seek a mechanistic understanding of cyclic softening in Sn-rich alloys. The equal channel angular pressing (ECAP) was applied to modify the microstructure of the solder alloy by breaking up the needlelike Ag3Sn intermetallic phase into fine granules and by reducing the large beta-Sn dendrites into smaller and equiaxed grains. The extruded alloys were subjected to strain-controlled fatigue test at various strain amplitudes. It was found that the extruded alloy exhibited a sharp decrease of the stress amplitude within the initial few cycles compared with the as-cast alloy. After only a few cycles, the alloy suffered from noticeable surface damage. In situ scanning electron microscopy observations of the cyclic bending specimens revealed an approximately logarithmic relationship between crack density and the number of cycles. A theoretical model of microcrack accumulation was constructed to explain the rapid cyclic softening behavior. The predicted results, based on the model, agreed well with the experimental data and indicated that the rapid softening had resulted from an increased tendency for grain boundary cracking in the ECAPed microstructure due to the increase in the,rain boundary area per unit volume and the reduced resistance of Ag3Sn to grain boundary sliding.
原文出处	://WOS:000259785300008
公开日期	2012-04-13
内容类型	期刊论文
源URL	[http://210.72.142.130/handle/321006/33409]
专题	金属研究所_中国科学院金属研究所
推荐引用方式 GB/T 7714	Q. S. Zhu,Z. G. Wang,Q. L. Zeng,et al. Rapid cycle-dependent softening of equal channel angularly pressed Sn-Ag-Cu alloy[J]. Journal of Materials Research,2008,23(10):2630-2638.
APA	Q. S. Zhu,Z. G. Wang,Q. L. Zeng,S. D. Wu,&J. K. Shang.(2008).Rapid cycle-dependent softening of equal channel angularly pressed Sn-Ag-Cu alloy.Journal of Materials Research,23(10),2630-2638.
MLA	Q. S. Zhu,et al."Rapid cycle-dependent softening of equal channel angularly pressed Sn-Ag-Cu alloy".Journal of Materials Research 23.10(2008):2630-2638.