Crack bridging is an important source of crack propagation resistance in many materials and the bridging stress distribution as a function of crack opening displacement is widely believed to represent a true material property uninfluenced by sample geometry, loading conditions, and other extrinsic factors. Accordingly, accurate measurement of the bridging...
Depth-profiled Doppler broadening spectroscopy of positron annihilation on the cyclic fatigue-induced fracture surfaces of three amorphous Zr₄₄Ti₁₁Ni₁₀Cu₁₀Be₂₅ metallic glass specimens reveals the presence of a 30–50 nm layer of increased free volume that is generated by the propagating fatigue crack tip. The presence and character of this fatigue transformation zone...
OBJECTIVES: Secondary caries is the most common reason for composite restoration replacement and usually forms between dentin and the filling. The objective of this study was to investigate the combined effect of cyclic loading and bacterial exposure on bacterial penetration into gaps at the interface between dentin and resin composite...
Bulk metallic glasses (BMGs) have been reported to have large variability in mode I fracture toughness. In this study, alternating soft and hard regions were created in a Zr₅₂.₅Ti₅Cu₁₈Ni₁₄.₅Al₁₀ (at%) BMG via mechanical imprinting at room temperature. While only 50% of as-cast samples demonstrated plastic deformation during mode I fracture...
The fatigue crack growth rates for nickel-based superalloy Haynes 282 were measured at temperatures of 550, 650, and 750 °C using compact tension specimens with a load ratio of 0.1 and cyclic loading frequencies of 25 Hz and 0.25 Hz. Increasing the temperature from 550 to 750 °C caused the...
Small crack fatigue is a widely recognized problem in the fatigue of materials; however, there has been limited progress in developing methods for predicting small crack fatigue behavior. In this paper, small crack effects due to crack bridging are addressed. A fatigue threshold R-curve was measured for a 99.5% pure...
Interstitially filled skutterudites are a promising class of state-of-the-art thermoelectric
materials. Although thermoelectrics are exposed to significant thermal stresses, little
information is known about the fracture toughness of interstitially doped skutterudites. This
work explores the fracture toughness of undoped Co₄Sb₁₂ and indium doped In₀.₁Co₄Sb₁₂
skutterudites using three methods: 1) Vickers...
Small crack fatigue is a widely recognized problem in the fatigue of materials; however, there has been limited progress in developing methods for predicting small crack fatigue behavior. In this paper, small crack effects due to crack bridging are addressed. A fatigue threshold R-curve was measured for a 99.5% pure...
Small crack fatigue is a widely recognized problem in the fatigue of materials; however, there has been limited progress in developing methods for predicting small crack fatigue behavior. In this paper, small crack effects due to crack bridging are addressed. A fatigue threshold R-curve was measured for a 99.5% pure...
Small crack fatigue is a widely recognized problem in the fatigue of materials; however, there has been limited progress in developing methods for predicting small crack fatigue behavior. In this paper, small crack effects due to crack bridging are addressed. A fatigue threshold R-curve was measured for a 99.5% pure...