Phase transformation in boron under shock compression

Collective nature of plasticity in mediating phase transformation under shock compression

An open question in the behavior of metals subjected to shock is the nature of the deformation that couples to the phase transformation process. Experiments to date cannot discriminate between the role of known deformation processes, such as twinning or dislocations accompanying a phase change, and modes that can become active only in extreme environments. We show that a deformation mode not pr...

Shock-induced phase transformation in tantalum.

A TEM study of pure tantalum and tantalum-tungsten alloys explosively shocked at a peak pressure of 30 GPa is presented. While no omega phase was found in shock-recovered pure Ta and Ta-5W which mainly contain a cellular dislocation structure, a shock-induced omega phase was found in Ta-10W which contains evenly distributed dislocations with a density higher than 1 × 10(12) cm( - 2). The shock-...

Strength of Polycrystalline Ceramics under Shock Compression

Boron under Pressure: Phase Diagram and Novel High-pressure Phase

Boron has a unique chemistry, responsible for remarkable complexities even in the pure element. I review some of the history of the discovery of this element, and recent surprises found in boron under pressure. I discuss the recent discovery of a new high-pressure phase, γ-B28, consisting of icosahedral B12 clusters and B2 pairs in a NaCl-type arrangement: (B2)(B12), and displaying a significan...

STRUCTURAL INTEGRITY CHANGES IN THE Zr-Nb ALLOY DURING HYDRIDE PHASE TRANSFORMATION UNDER THE THERMAL SHOCK

Structural changes and properties of zirconium alloy subjected to the thermal shock in the solar furnace were investigated. Specimens were prepared from unirradiated cold-worked RBMK Zr-2.5Nb fuel channel pressure tube material after adding hydrogen to the sections of the tubes up to 150 ppm. Tests were done at temperatures up to 1460 C and heating rates 50-83 C per second. After thermal treatm...