On the Distinction Between Plasticity- and Roughness-Induced Fatigue Crack Closure

被引:0
作者
Sotomi Ishihara
Yuya Sugai
Arthur J. McEvily
机构
[1] University of Toyama,Department of Mechanical Engineering
[2] University of Connecticut,Department of Chemical, Materials, Biomolecular Engineering
来源
Metallurgical and Materials Transactions A | 2012年 / 43卷
关键词
Fatigue Crack; Fatigue Crack Growth; Crack Closure; Fatigue Crack Growth Rate; Lateral Contraction;
D O I
暂无
中图分类号
学科分类号
摘要
A series of experiments has been carried out to determine why some alloys display plasticity-induced fatigue crack closure (PIFCC), whereas other alloys display roughness-induced crack closure (RIFCC). Two alloys were studied, the aluminum alloy 6061-T6 (PIFCC) and a steel of comparable yield strength, S25C (RIFCC). The experiments included the determination of the crack-opening levels as a function of ΔK, da/dN as a function of ΔKeff – ΔKeffth, removal of the specimen surface layers, removal of the crack wake, the determination of crack front shapes, crack surface roughness profiles, and the degree of lateral contraction in the plastic zone at a crack tip. Based on crack tip opening displacement (CTOD) considerations, it is concluded that PIFCC is favored in alloys of low modulus and relatively low yield strength. In addition, a low strain-hardening rate such as for the 6061 alloy will favor PIFCC. Steels with a higher modulus and a higher strain-hardening rate than 6061 will, in general, exhibit RIFCC, even at comparable yield strength levels. In ferritic steels, the fracture surface roughness and consequently the crack-opening level will increase as the coarseness of the microstructure increases.
引用
收藏
页码:3086 / 3096
页数:10
相关论文
共 33 条
[1]  
Elber W.(1970)undefined Eng. Fract. Mech. 2 37-45
[2]  
Minakawa K.(1986)undefined Metall. Trans. A 17A 1787-95
[3]  
Levan G.(1978)undefined J. Appl. Mech. 45 267-76
[4]  
McEvily A.J.(2009)undefined Fatigue Frac. Eng. Mat. Struct. 32 284-85
[5]  
Budiansky B.(1991)undefined Eng. Fract. Mech. 40 571-84
[6]  
Hutchinson J.(1988)undefined Eng. Fract. Mech. 31 703-12
[7]  
McEvily A.J.(1977)undefined Met. Sci. 11 274-74
[8]  
McEvily A.J.(2002)undefined Int. J. Fatigue 24 1169-45
[9]  
Eifler D.(2007)undefined Int. J. Fatigue 29 2737-66
[10]  
Macherauch E.(2005)undefined Int. J. Fatigue 27 862-93