scholarly journals Hydrogen-Enhanced Fatigue Crack Growth in a Single-Edge Notched Tensile Specimen Under In-Situ Hydrogen Charging Inside an Environmental Scanning Electron Microscope

2018 ◽  
Author(s):  
Di Wan ◽  
Yun Deng ◽  
Jan Inge Hammer Meling ◽  
Antonio Alvaro ◽  
Afrooz Barnoush
Keyword(s):  
Fatigue Crack ◽  
Electron Microscope ◽  
Fatigue Crack Growth ◽  
Scanning Electron Microscope ◽  
Crack Growth ◽  
Tensile Specimen ◽  
Environmental Scanning ◽  
Single Edge ◽  
Scanning Electron

scholarly journals Influence of Multi-Holes on Fatigue Behaviors of Cast Magnesium Alloys Based on In-Situ Scanning Electron Microscope Technology

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1700 ◽  
Author(s):  
Xi-Shu Wang ◽  
Chang-Hao Tan ◽  
Juan Ma ◽  
Xiao-Dong Zhu ◽  
Qing-Yuan Wang
Keyword(s):  
Fatigue Crack ◽  
Electron Microscope ◽  
Crack Initiation ◽  
Scanning Electron Microscope ◽  
Magnesium Alloys ◽  
Mg17al12 Phase ◽  
Cast Magnesium Alloys ◽  
Cast Magnesium ◽  
Scanning Electron

The low cycle fatigue tests on the crack initiation and propagation of cast magnesium alloys with two small holes were carried out by using in-situ scanning electron microscope (SEM) observation technology. The fatigue crack propagation behaviors and fatigue life, which are affected by two small artificial through holes, including the distances between two holes and their locations, were discussed in detail based on the experimental results and the finite element analysis (FEA). The results indicated that the fatigue multi-cracks occurred chiefly at the edges of two holes and the main crack propagation was along the weak dendrite boundary with the plastic deformation vestiges on the surface of α-Mg phase of cast AM50 and AM60B alloys. The fatigue cracking characteristics of cast AZ91 alloy depended mainly on the brittle properties of β-Mg17Al12 phase, in which the multi-cracks occurred still at the edges of two holes and boundaries of β-Mg17Al12 phase. The fatigue crack initiation position of cast magnesium alloys depends strongly on the radius of curvature of through hole or stress concentration factor at the closed edges of two through holes. In addition, the fatigue multi-cracks were amalgamated for the samples with titled 45° of two small holes of cast Mg-Al alloys when the hole distance is less than 4D (D is the diameter of the small hole).

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