Improvement of fatigue-crack growth resistance by grain-boundary reaction precipitates at high temperature

1990 ◽  
Vol 25 (8) ◽  
pp. 3785-3789 ◽  
Author(s):  
Hiroshi Iizuka ◽  
Manabu Tanaka
Keyword(s):  
Fatigue Crack ◽  
High Temperature ◽  
Fatigue Crack Growth ◽  
Grain Boundary ◽  
Crack Growth ◽  
Crack Growth Resistance ◽  
Fatigue Crack Growth Resistance ◽  
Boundary Reaction

Effect of Microstructure on Fatigue Crack Growth Resistance of Magnesium Alloy under Biaxial Stress

2005 ◽  
Vol 297-300 ◽  
pp. 1559-1564 ◽  
Author(s):  
Yasumi Ito ◽  
Akira Shimamoto
Keyword(s):  
Fatigue Crack ◽  
High Temperature ◽  
Magnesium Alloy ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Temperature Region ◽  
Heat Treating ◽  
Crack Growth Resistance ◽  
High Temperature Region ◽  
Fatigue Crack Growth Resistance

Fatigue crack propagation tests are conducted on magnesium alloy, cruciform specimens under biaxial and uniaxial loadings by using the biaxial fatigue tester which was developed by the authors. We investigate the effect of microstructures of specimens on fatigue crack growth resistance under biaxial stresses. From electron-microscope observations of a fatigue fracture and microstructure observations, it becomes clear that the mechanical properties of a magnesium-alloy, AZ31B, are greatly influenced by the diameter of crystal grains. We find that static tensile strength falls by heat-treating in the high temperature region where the diameter of crystal grains of an X-Y plane becomes large. We also find that the crack progress velocity under equal biaxial stresses gets faster by heat-treating in the high temperature region where the diameter of crystal grain of a Z-X plane becomes large.

Improvement of Fatigue Crack Growth Resistance by Serrated Grain Boundary at High Temperature

1991 ◽  
Vol 113 (1) ◽  
pp. 9-14 ◽  
Author(s):  
Hiroshi lizuka ◽  
Manabu Tanaka ◽  
Fumio Ashihara
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Crack Growth ◽  
Growth Rates ◽  
Fatigue Cracks ◽  
Crack Growth Resistance ◽  
Fatigue Crack Growth Resistance ◽  
Crack Growth Rates

Effects of serrated grain boundaries on the improvement of fatigue-crack growth resistance were investigated using austenitic 21Cr-4Ni-9Mn heat-resisting steel at 973K in air. Grain boundaries were serrated by grain-boundary reaction precipitates. The crack-growth rates were considerably decreased in the specimens with the serrated grain boundaries. The fatigue cracks were largely deflected by the serrated grain boundaries, and brittle intergranular fracture was retarded. The improvement of the crack-growth resistance was obtained especially under the conditions of low crack-growth rates of less than 30 μm/cycle. The widths and the heights of the deflected portions of the cracks were in the range from about a few μm to 30 μm.

Super Light Alloy Al-Cu-Li-Fatigue Crack Growth Resistance at Temperatures 293 and 77K

2000 ◽  
pp. 113-118
Author(s):  
V. V. Eremenko ◽  
Yu. A. Pokhil ◽  
L. F. Yakovenko ◽  
E. N. Aleksenko ◽  
I. N. Fridlyander
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Crack Growth Resistance ◽  
Light Alloy ◽  
Fatigue Crack Growth Resistance
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