Thermal expansion of alpha-uranium single crystals

Intrinsically localized vibrations and the mechanical properties of α-uranium

“…Therefore, understanding the anomalous mechanical-deformation behavior of uranium in the presence of ILMs requires a detailed picture of the ILM strain fields. Here, after a discussion of the anomaly in the mechanical deformation [7] and its coincidence with ILM formation, we attempt to obtain information on the ILM strains by looking at the anisotropic thermal expansion behavior [8,9]. By extension we also argue that a transition from positive to negative thermal expansion along [0 1 0] is caused by the ILM strains.…”

Impact of intrinsic localized modes of atomic motion on materials properties

“…The anisotropic thermal expansion of α-U was measured along all three crystallographic directions on a single crystal by Lloyd [15]. Figure 3a shows the results along with an indication of the ILM activation temperature, ~450 K [10].…”

Thermomechanical Response of Polycrystalline alpha-Uranium

“…Of particular interest, for the current work, is the anisotropy of the thermal expansion properties. In the b direction, the coe cient of thermal expansion is negative or near zero, while both the a and c direction exhibit positive thermal expansion [4,5].…”

“…In the b direction, the coe cient of thermal expansion is negative or near zero, while both the a and c direction exhibit positive thermal expansion [4,5]. These stresses have been shown to induce plastic relaxation mechanisms [30] and leave annealed polycrystals with inter-granular residual stresses at room temperature.…”

“…Orthorhombic ↵-uranium exhibits high single crystal anisotropy in its elastic [3], thermal expansion [4,5] and plastic response [6,7], which leads to highly anisotropic textured polycrystals. In addition to the anisotropy at a given temperature, studies on single crystals have shown these properties possess individual temperature dependencies [2,3,5].…”