Fatigue Striations and Fissures in 2024-T3 Aluminum Alloy

2007 ◽  
Vol 567-568 ◽  
pp. 397-400 ◽  
Author(s):  
A.J. McEvily ◽  
Masahiro Endo ◽  
S. Cho ◽  
J. Kasivitamnuay ◽  
Hisao Matsunaga
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Fracture Surface ◽  
Crack Growth ◽  
Fatigue Striations ◽  
Aluminum Alloy 2024 ◽  
Low K

A study has been made of the striations and fissures developed in the aluminum alloy 2024-T3 during fatigue crack growth. Fissures were found to form on inclined facets. They were uniformly spaced as the result of a shielding process. Striation spacings were in accord with da/dN values at the higher levels of K investigated, but at low K levels striation spacings were larger than the corresponding da/dN values. The percentage of the fracture surface containing striations varied with the K level, ranging from less than 1 % at low K levels to 80 % at higher K levels. The reason for the discrepancy between the spacing of striations and the corresponding da/dN values is discussed.

AN EVALUATION OF THE EFFECT OF SHOT PEENING ON THE FATIGUE CRACK GROWTH IN ALUMINUM ALLOY 2024 - T3

2015 ◽  
Author(s):  
Douglas Henrique da Silva Costa ◽  
Marcelo Augusto Santos Torres ◽  
Carlos Antonio Reis Pereira Baptista
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Shot Peening ◽  
Aluminum Alloy 2024

Micromechanisms of multistage fatigue crack growth in a high-strength aluminum alloy

2007 ◽  
Vol 55 (6) ◽  
pp. 1975-1984 ◽  
Author(s):  
Y. Xue ◽  
H. El Kadiri ◽  
M.F. Horstemeyer ◽  
J.B. Jordon ◽  
H. Weiland
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
High Strength ◽  
High Strength Aluminum Alloy

Estimation of Applied Stress at Fatigue Cracks of a Single Crystal Superalloy

2020 ◽  
Author(s):  
Daisuke Kobayashi ◽  
Katsuhiro Takama ◽  
Tomihiko Ikeda
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Fracture Surface ◽  
Single Crystal ◽  
Crack Growth ◽  
Applied Stress ◽  
Fatigue Crack Growth Rate ◽  
Single Crystal Superalloy

Abstract Needless to say, it is important to estimate the stress applied to a material when conducting failure analysis. In recent years, a material assessment method using electron back-scatter diffraction (EBSD) has been developed. It has been reported that a characteristic misorientation distribution corresponding to the fracture mode is seen in cross-sectional EBSD observation near the fracture surface of a Ni-based superalloy. Furthermore, the authors discovered EBSD striations on the crack cross-section, which is formed with each fatigue crack growth during a turbine shut-down process. This was discovered in misorientation analysis on a single-crystal superalloy blade used in a commercial land-based gas turbine. Since Ni-based superalloys have high deformation resistance, they do not undergo enough ductile deformation to form striations at the crack tip on the fracture surface during fatigue crack growth, and, as a result, striations corresponding to cyclic loadings are rarely observed in fractography. Even in such a Ni-based superalloy with brittle crack growth, the fatigue crack growth rate and the applied stress can be estimated by measuring EBSD striation spacing in misorientation analysis. However, a practical problem in assessment is that the resolution limit fixed with field emission scanning electron microscopes (FE-SEM) determine the range in which crack growth rate can be assessed. Hence, it is difficult to clearly discriminate the EBSD striations when the fatigue crack growth rate is too low, such as in the low stress intensity factor range (ΔK) region. The applied stress can be calculated from ΔK. Therefore, in this paper, in order to estimate the applied stress during fatigue crack growth, we focused on estimating ΔK by measuring the plastic zone size along the crack growth.

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