Temperature dependence of fatigue–fracture-mode change in Cu–SiO2 alloy

2002 ◽  
Vol 24 (9) ◽  
pp. 943-948 ◽  
Author(s):  
H MIURA ◽  
T SAKAI ◽  
M KATO
Keyword(s):  
Temperature Dependence ◽  
Fatigue Fracture ◽  
Fracture Mode ◽  
Mode Change

Effect of Voids on Thermal Fatigue Reliability of Lead-Free Solder Joints

2002 ◽  
Author(s):  
Qiang Yu ◽  
Do-Seop Kim ◽  
Tadahiro Shibutani ◽  
Toshiaki Inoue ◽  
Nobuyuki Sadakata
Keyword(s):  
Fatigue Strength ◽  
Fatigue Test ◽  
Fatigue Fracture ◽  
Fracture Mode ◽  
Solder Joints ◽  
Equivalent Plastic Strain ◽  
Lead Free ◽  
Lead Free Solder ◽  
Shear Fatigue ◽  
Free Solder

There have been serious debates about whether Pb should be removed from solder joints, in view of environmental problems. These debates have now developed to the extent that a remarkable movement to establish regulations for the removal of Pb has emerged, especially in European countries and Japan. Therefore, many studies are aggressively being undertaken to develop technologies for replacing Sn-Pb solder with a lead-free alternative. From the results obtained so far, it has been proven that the fatigue strength in lead-free solder joints is almost equivalent to the fatigue strength of Sn-Pb eutectic solder joints. However, the other problem is that voids are easily formed in lead-free solder joints during the reflow process, and the effects of void formation on the fatigue strength of solder joints has attracted attention. In this study, the relationship between formation of voids and fatigue fracture mode and fatigue strength of solder joints was examined using FEM (finite element method) analysis and mechanical shear fatigue test. From the results of FEM analysis, it has been found that the equivalent plastic strain and shear strain of solder joints with voids are not always larger than those of solder joints without voids and the magnitude of the strains relate to the position and size of voids in solder joints. However, the difference of the strains is not so great as to affect the fatigue strength of solder joints. It has also been proven from the mechanical shear fatigue test that the fatigue fracture mode of solder joints with voids is similar to that of solder joints without voids and fatigue strength in both cases is also almost equivalent.

Fracture-Mode Change in Alumina-Silicon Carbide Composites Doped with Rare-Earth Impurities

2003 ◽  
Vol 86 (10) ◽  
pp. 1789-1792 ◽  
Author(s):  
Zhen-Yan Deng ◽  
You Zhou ◽  
Manuel E. Brito ◽  
Jian-Feng Yang ◽  
Tatsuki Ohji
Keyword(s):  
Silicon Carbide ◽  
Rare Earth ◽  
Fracture Mode ◽  
Mode Change ◽  
Rare Earth Impurities

Interior-Induced Fracture Mechanism of High Cleanliness Spring Steel (JIS SWOSC-V) in Very High Cycle Regime

2015 ◽  
Vol 664 ◽  
pp. 209-218 ◽  
Author(s):  
Taku Miura ◽  
Takayuki Sakakibara ◽  
Takanori Kuno ◽  
Akira Ueno ◽  
Shoichi Kikuchi ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Fatigue Fracture ◽  
Fracture Mode ◽  
Fracture Mechanism ◽  
Fatigue Crack Initiation ◽  
Fatigue Tests ◽  
Spring Steel ◽  
Topographic Analysis ◽  
Very High

In order to investigate the interior-induced fatigue crack propagation behavior of high cleanliness valve spring steel (JIS SWOSC-V), rotating bending fatigue tests were performed for various kinds of specimens with different hardness or surface finishings. The harder specimen with higher compressive residual stress showed longer fatigue life. The electrochemical polished specimen pre-treated with shot peening showed almost same fatigue life as the shot-peened specimen in spite of the difference in surface roughness. After fatigue tests, fracture surfaces were observed using a scanning electron microscope (SEM) to evaluate the fatigue fracture mechanism. Most specimens failed in surface-induced fracture mode due to high cleanliness; however, some specimens failed in interior-induced fracture mode in the very high cycle regime. Although non-metallic inclusions were not observed at interior fatigue crack initiation sites, 2 types of significant microstructures (with smooth surface or granular surface) were observed. EBSD analysis, profile analysis and computational simulation using a fracture surface topographic analysis (FRASTA) method were performed to investigate the mechanism of the interior-induced fatigue fracture caused by the microstructure at defect without any inclusion.

Adhesive wood joints under quasi-static and cyclic fatigue fracture Mode II loads

2019 ◽  
Vol 123 ◽  
pp. 40-52 ◽  
Author(s):  
Gaspard Clerc ◽  
Andreas J. Brunner ◽  
Sébastien Josset ◽  
Peter Niemz ◽  
Frédéric Pichelin ◽  
...  
Keyword(s):  
Fatigue Fracture ◽  
Fracture Mode ◽  
Cyclic Fatigue ◽  
Mode Ii

Effect of Non-Metallic Inclusion Size and Residual Stresses on Gigacycle Fatigue Properties in High Strength Steel

2008 ◽  
Vol 44-46 ◽  
pp. 33-42 ◽  
Author(s):  
Kazuaki Shiozawa ◽  
L. Lu
Keyword(s):  
Fatigue Life ◽  
Crack Initiation ◽  
Residual Stresses ◽  
Fatigue Fracture ◽  
Fracture Mode ◽  
Stress Amplitude ◽  
High Strength ◽  
Inclusion Size ◽  
Metallic Inclusion ◽  
Amplitude Level

Fatigue fracture of some high-strength steels occurs at small defect in the subsurface zone of a material at low stress amplitude level and in a high-cycle region of more than 106 cycles (gigacycle fatigue life), whereas surface fatigue crack initiation occurs at high-stress amplitude and low cycles. There is a definite stress range where the crack initiation site changes from a surface to a subsurface defect, giving a step-wise S-N curve or a duplex S-N curve. From the experimental results, fatigue fracture mode was classified into three types, such as, surface inclusion induced fracture mode, subsurface inclusion induced fracture mode without granular bright facet (GBF) area and that with the GBF, depending on stress amplitude level and stress ratio. The GBF area was observed in the vicinity of a non-metallic inclusion at the fracture origin inside the fish-eye in gigacycle fatigue regime. It was made clear from the discussion with fracture mechanics that the transition of fracture mode was affected by compressive residual stresses on the specimen surface. Fracture-mode transition diagram was proposed through the experimental and theoretical investigation. Also, from the evaluation of the fatigue life based on the estimated subsurface crack growth rate from the S-N data, effect of inclusion size on the dispersion of fatigue life was explained, and S-N curve for subsurface inclusion-induced fracture depended on the inclusion size was provided.

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