The effects of environmental media on the corrosion fatigue fracture behavior of 25CrMo steel were investigated. The media include air, and a 3.5 wt.% and a 5.0 wt.% NaCl solutions. Experimental results indicate that the media induces the initiation of corrosion fatigue cracks at multiple sites. The multi-cracking sites cause the changes in the crack growth directions, the crack growth rate dur...

While Portland cement concrete (PCC) overlay has been increasingly used as a rehabilitation technique for deteriorated PCC pavements in the last decade, reflective cracking places a major limit on its durability performance. The use of ultra ductile concrete named Engineered Cementitious Composite (ECC) should arrest such failure mode and greatly enhance the long term performance of the overlai...

A method utilizing expansion of a diaphragm-type film specimen was developed to study in vitro biodegradation of poly(etherurethane urea) (PEUU) under conditions of dynamic loading (fatigue). A finite element model was used to describe the strain state, which ranged from uniaxial at the edges of the film to balanced biaxial tensile strain at the center. During testing, the film was exposed to a...

Through investigating and comparing the fatigue behavior of an as-forged Mg-6.7Zn-1.3Y-0.6Zr (wt.%) alloy before and after solid solution treatment (T4) in laboratory air, the effect of T4 treatment on fatigue crack initiation was disclosed. S-N curves illustrated that the fatigue strength of as-forged samples was 110 MPa, whereas the fatigue strength of T4 samples was only 80 MPa. Observations...

The effects of corrosive media on rotating bending fatigue lives (the cyclic numbers from 104 to 108) of different aluminum alloys were investigated, which involved the corrosion fatigue lives of five kinds of aluminum alloys in air, at 3.5 wt. % and 5.0 wt. % NaCl aqueous solutions. Experimental results indicate that corrosive media have different harmful influences on fatigue lives of differe...

Increasing use of aluminum shape castings in automotive and aerospace industries has drawn great attention to fatigue properties of cast aluminum components. The fatigue resistance of aluminum castings strongly depends upon the presence of casting flaws and characteristics of microstructural constituents. The existence of casting flaws significantly reduces fatigue crack initiation life. In the...

Stress corrosion cracking (SCC) of metals is an issue of major concern in engineering since this phenomenon causes many catastrophic failures of structural components in aggressive environments. SCC is even more harmful under cathodic conditions promoting the phenomenon known as hydrogen assisted cracking (HAC), hydrogen assisted fracture (HAF) or hydrogen embrittlement (HE). A common way to as...

The fatigue properties of ultrathin protective coatings on silicon thin films were investigated. The cohesive and delamination fatigue properties of 22 nm-thick atomic-layered-deposited (ALD) titania were characterized and compared to that of 25 nm-thick alumina. Both coatings were deposited at 200 °C. The fatigue rates are comparable at 30 °C, 50% relative humidity (RH) while they are one orde...

A unified multiaxial fatigue damage model based on a characteristic plane approach is proposed in this paper, integrating both isotropic and anisotropic materials into one framework. Compared with most available critical plane-based models for multiaxial fatigue problem, the physical basis of the characteristic plane does not rely on the observations of the fatigue crack in the proposed model. ...