Recent seismological observations reveal the presence of seismic anisotropy in localized regions at the base of the mantle within an otherwise isotropic lower mantle. These regions can be placed in a tectonic context, corresponding to locations of paleosubduction and plume upwelling. This project works toward determining whether the observed seismic anisotropy may be explained by the developmen...

Nickel-rich NiAl foams, consisting of open cells with hollow struts and exhibiting two relative densities (5.0 and 6.6 pct) and average cell sizes (1.27 and 0.85 mm), were creep tested between 800 °C and 1100 °C under compressive stresses between 0.10 and 1.50 MPa. For stresses lower than 0.50 MPa, the foams exhibit secondary creep with power-law behavior characterized by creep exponents and ac...

Recent experimental studies of the hot isostatic consolidation of Ti-6Al-4V–coated SiC fibers contained in cylindrical canisters have revealed an unexpectedly high rate of creep densification. A creep consolidation model has been developed to analyze its origin. The initial stage of consolidation has been modeled using the results of contact analyses for perfectly plastic and power-law creeping...

Experimental data (Thornton et al., 1997) show that relaxation proceeds more rapidly (a greater slope on a log-log scale) than creep in ligament, a fact not explained by linear viscoelasticity. An interrelation between creep and relaxation is therefore developed for ligaments based on a single-integral nonlinear superposition model. This interrelation differs from the convolution relation obtai...

The appearance of denuded zones following low stress creep in particle-containing crystalline materials is both a microstructural prediction and observation often cited as irrefutable evidence for the Nabarro– Herring (N–H) mechanism of diffusional creep. The denuded zones are predicted to be at grain boundaries that are orthogonal to the direction of the applied stress. Furthermore, their dime...

We present a new class of TiBw/Ti6Al4V composites with a network reinforcement architecture that exhibits a significant creep resistance compared to monolithic Ti6Al4V alloys. Creep tests performed at temperatures between 773 K and 923 K and stress range of 100 MPa-300 MPa indicate both a significant improvement of the composites creep resistance due to the network architecture made by the TiB ...

This paper summarizes a cooperative research program between the USDA Forest Service, Forest Products Laboratory (FPL), in Madison, Wisconsin, and Forintek Canada Corp. in Vancouver, British Columbia, Canada. This research program provided detailed creep–rupture and some creep information for composite panel products. Commercially produced plywood, oriented strandboard (OSB), and minimally alig...

In the presented article, the temperature effect was studied on creep properties and fracture behaviors of AlSi12Cu3Ni2MgFe aluminum-silicon alloys, unreinforced and reinforced with SiO2 nano-particles. For such objective, standard specimens were fabricated by gravity casting and stir-casting methods, for aluminum alloys and nano-composites, respectively. Then, force-controlled creep...

BACKGROUND Several physiological and pathological conditions in daily life cause sustained static bending or torsion loads on the spine resulting in creep of spinal segments. The objective of this study was to determine the effects of creep and recovery on the range of motion, neutral zone, and neutral zone stiffness of thoracolumbar multi-level spinal segments in flexion, extension, lateral be...

In order to provide creep mechanical parameters for the clinical application of both traditional and reserved anatomy femoral artificial joint replacements, simulated hip replacement femoral stress relaxation and creep experiments were performed. Twenty-four corpse femoral specimens were obtained, with 8 specimens being randomly assigned to the control group and 8 specimens being randomly assig...