The metals which have the bcc structure at and below room temperature include iron, refractory metals of Groups VA and VIA, and alkali metals. Experimental and theoretical investigations of deformation behavior carried out in the last twenty years are reviewed. Attention is concentrated mainly on low temperature properties where many anomalous features have been discovered. The phenomena discussed include slip asymmetry, failure of the Schmid law of critical resolved shear stress, the observation of anomalous slip in very pure metals and alloys, solution softening, and the ductile-brittle transition.

Some surprising features of the plastic deformation of body-centered cubic metals and alloys

Multiscale modeling of plastic deformation of molybdenum and tungsten: I. Atomistic studies of the core structure and glide of 1/2〈1 1 1〉 screw dislocations at 0 K

The behavior of the screw dislocation core in the presence of an external shear stress has been examined for the body-centered cubic and hexagonal close-packed phases of a model sodium lattice, usi...

Influence of Shear Stress on Screw Dislocations in a Model Sodium Lattice

Multiscale modeling of plastic deformation of molybdenum and tungsten: II. Yield criterion for single crystals based on atomistic studies of glide of 1/2〈111〉 screw dislocations

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

High-purity niobium crystals with a centre-triangle axial orientation were deformed in steps at 77°K. Each crystal was cut to a square cross-section and a reference grid applied to two adjacent surfaces before deformation. At each deformation step the lengths and orientations of the grid sides were determined, and using this information the amounts of slip on eight independent systems of {110} type were calculated. The results showed that most of the deformation occurred on the lightly stressed systems (011) [111] and (011) [111] with very little slip on the primary (101) [111] and conjugate (101) [111] systems. This analysis confirms earlier observations on high purity niobium deformed at low temperatures, which showed that (011) slip lines predominated (anomalous slip). The present data show that the conjugate Burgers vector is almost twice as active as the primary. In the earlier stages of deformation the straining proceeded by a series of small load drops, but later the curve became smoo...

G. Taylor

Papers

Anomalous slip in high-purity niobium single crystals deformed at 77°K in tension