Flow Stress in Submicron BCC Iron Single Crystals: Sample-size-dependent Strain-rate Sensitivity and Rate-dependent Size Strengthening

Size Dependent Acoustical Properties of bcc Metal

The ultrasonic attenuation is evaluated at 300 K along [100], [110], and [111] directions for the characterization of bcc metal Ta. The size of the metal is considered in nanorange. Ultrasonic velocity, Grüneisen parameter and acoustic coupling constant that depend on second and third order elastic constants are calculated for determination of ultrasonic attenuation coefficient. Second and thir...

False discovery rate, sensitivity and sample size for microarray studies

MOTIVATION In microarray data studies most researchers are keenly aware of the potentially high rate of false positives and the need to control it. One key statistical shift is the move away from the well-known P-value to false discovery rate (FDR). Less discussion perhaps has been spent on the sensitivity or the associated false negative rate (FNR). The purpose of this paper is to explain in s...

Pre-straining effects on the power-law scaling of size-dependent strengthening in Ni single crystals

We report experimental and three-dimensional discrete dislocation dynamics measurements to characterize the effect of high starting dislocation density on size-affected flow. Microcrystals were focused ion beam milled into a pre-strained bulk Ni single crystal to obtain a dense heterogeneous dislocation cell structure. The strength-scaling exponent is shown to decreases considerably with increa...

A Micromechanical Model of Hardening, Rate sensitivity and Thermal Softening in BCC Single Crystals

The present paper is concerned with the development of a micromechanical model of the hardening, rate-sensitivity and thermal softening of b.c.c. crystals. In formulating the model we specifically consider the following unit processes: double-kink formation and thermally activated motion of kinks; the close-range interactions between primary and forest dislocations, leading to the formation of ...

Temperature and strain-rate dependence of the flow stress of tantalum single crystals in cyclic deformation