Plastic mismatch effect on plasticity induced crack closure: Fatigue crack propagation perpendicularly across a plastically mismatched interface

2018 ◽  
Vol 42 (3) ◽  
pp. 597-611 ◽  
Author(s):  
Xiao-Xiong Song ◽  
Yi-Bo Shang ◽  
Hui-Ji Shi ◽  
Li-Sha Niu ◽  
Zhao-Xi Wang
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Crack Closure ◽  
Plasticity Induced Crack Closure ◽  
Mismatch Effect

scholarly journals P-Texture Effect on the Fatigue Crack Propagation Resistance in an Al-Cu-Mg Alloy Bearing a Small Amount of Silver

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2481 ◽  
Author(s):  
Yangcheng Hu ◽  
Zhiyi Liu ◽  
Qi Zhao ◽  
Song Bai ◽  
Fei Liu
Keyword(s):  
Electron Microscopy ◽  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Crack Closure ◽  
High Intensity ◽  
Damage Tolerance ◽  
Mg Alloy ◽  
Random Texture ◽  
Texture Effect

P-texture effect on the fatigue crack propagation (FCP) resistance in an Al-Cu-Mg alloy containing a small amount of Ag, is investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron back scattering diffraction (EBSD). Results shows that the high intensity P-texture sheet has lower σ0.2/σb, lower FCP rate and higher damage tolerance than random texture sheet. Fracture analysis indicates that the striations spacing of high intensity P-texture sheet is much smaller than that of random texture sheet and it has a rougher fatigue fracture surface, which causes a significant roughness induced crack closure (RICC) effect. The calculation results manifest that high intensity P-texture sheet possesses a higher crack closure level reaching 0.73 as compared to random texture sheet (only 0.25). The statistical analysis results reveal the P-grains have large twist angle of 105–170° and tilt angle of 5–60° with neighboring grains, which is similar to Goss-grains. This is the fundamental reason that P-texture sheet has the same FCP resistance and induces fatigue crack deflection as Goss-texture sheet. Additionally, the most {111} slipping planes of P-grains are distributed in the range of 30–50° deviating from transverse direction of the sheet. This results in more {111} slipping planes to participate in cyclic plastic deformation, which is beneficial to reduce fatigue damage accumulation and improve the damage tolerance of Al-Cu-Mg-Ag alloy.

Prestrain Influence on Fatigue Crack Propagation in a 304L Stainless Steel

2009 ◽  
Author(s):  
Kokleang Vor ◽  
Catherine Gardin ◽  
Christine Sarrazin-Baudoux ◽  
Jean Petit ◽  
Claude Amzallag
Keyword(s):  
Growth Rate ◽  
Stainless Steel ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Crack Propagation ◽  
Crack Growth ◽  
Fatigue Crack Propagation ◽  
Crack Closure ◽  
Threshold Region ◽  
304L Stainless Steel

The scope of this study is to investigate the effect of tensile prestrain on crack growth behavior in a 304L stainless steel. Fatigue crack propagation tests were performed on single-edge notched tension (SENT) raw specimens (0% of prestrain) and on prestrained specimens (2% and 10%). On one hand, it is found that the different levels of prestrain exhibit no significant influence on crack propagation in the high range of Stress Intensity Factor (SIF), where there is no detectable crack closure. On the other hand, a clear effect of prestrain on crack growth rate can be observed in the near threshold region where closure is detected. Thus, it can be concluded that the prestrain mainly affects the crack growth rate through its influence on the crack closure.

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