Exploring the role of reinforcement in controlling fatigue crack propagation behavior of perfluorosulfonic-acid membranes

2018 ◽  
Vol 43 (12) ◽  
pp. 6379-6389 ◽  
Author(s):  
Zhe Zhang ◽  
Shouwen Shi ◽  
Qiang Lin ◽  
Lei Wang ◽  
Zheng Liu ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Perfluorosulfonic Acid ◽  
Fatigue Crack Propagation Behavior ◽  
Propagation Behavior ◽  
Perfluorosulfonic Acid Membranes ◽  
Crack Propagation Behavior

The Role of Intermetallic Phases in Fatigue Crack Propagation Behavior of Al-Zn-Mg-Cu Alloys

2007 ◽  
Vol 555 ◽  
pp. 553-558 ◽  
Author(s):  
M. Vratnica ◽  
Z. Cvijović ◽  
K. Gerić ◽  
Zijah Burzić
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Volume Fraction ◽  
Fatigue Crack Propagation Behavior ◽  
Propagation Behavior ◽  
Cu Alloys ◽  
Crack Propagation Behavior

The aim of the present work is to determine the role of intermetallic (IM) phases in the fatigue crack propagation behavior of hot-forged Al-Zn-Mg-Cu alloys in T73 condition. To generate differences in the volume fraction and coarseness of various IM particles, the (Fe+Si) impurity level is varied from 0.23 to 0.37 mass%. The fatigue crack propagation tests are conducted in air at ambient temperature and a stress ratio R of 0.1. Characterization of the fatigue fracture surfaces is performed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). Quantified IM particles data for each alloy are then related to the fatigue properties and fractographic analysis results. It was found that almost all particles of the Fecontaining phases (primarily (Cu,Fe,Mn)Al3 and Al7Cu2Fe) are broken and not effective in hindering fatigue crack propagation. On the other hand, the Mg2Si and soluble phase particles smaller than those of the Fe-containing phases contribute beneficially to fatigue life. These particles increase the tortuosity of the crack path and retard the crack growth rate. The crack growth rate decreases as the volume fraction of coarse Fe-containing particles increases, because more secondary cracks are produced decreasing the effective stress intensity at the main crack tip.

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