α-钚在其整个温度范围内的多晶弹性模量。

Alpha-plutonium's polycrystalline elastic moduli over its full temperature range.

作者信息

Migliori A, Pantea C, Ledbetter H, Stroe I, Betts J B, Mitchell J N, Ramos M, Freibert F, Dooley D, Harrington S, Mielke C H

机构信息

Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.

出版信息

J Acoust Soc Am. 2007 Oct;122(4):1994-2001. doi: 10.1121/1.2767419.

DOI:10.1121/1.2767419

PMID:17902836

Abstract

alpha-plutonium's volume-corrected polycrystal elastic moduli were measured between 18 K and the upper limit of its occurrence, near 400 K. The two independent moduli for a polycrystal-bulk and shear-behave smoothly, indicating no phase transition. Both moduli show the same 50% increase on cooling, an order of magnitude larger than in other metals. The Debye temperature obtained from low-temperature elastic moduli, 207 K, significantly exceeds most previous estimates. The Gruneisen parameter gamma=5.3, obtained from the temperature dependence of the bulk modulus, is intermediate among previous estimates using other approaches, alpha-plutonium's Poisson ratio nu is low: 0.18, nearly temperature independent, and its small decrease on warming opposes usual behavior. The high gamma, large but equal bulk modulus and shear modulus fractional stiffening on cooling, and near-temperature-invariant nu are attributed to a single mechanism: 5-f electron localization-delocalization.

摘要

测量了α钚在18K至其出现的上限（接近400K）之间的体积校正多晶弹性模量。多晶体的两个独立模量——体模量和剪切模量——表现平滑，表明没有相变。在冷却时，两个模量都显示出50%的相同增长，比其他金属大一个数量级。从低温弹性模量获得的德拜温度为207K，大大超过了之前的大多数估计值。从体模量的温度依赖性获得的格林爱森参数γ = 5.3，在之前使用其他方法的估计值中处于中间水平。α钚的泊松比ν很低：0.18，几乎与温度无关，并且在升温时其微小下降与通常行为相反。高γ值、冷却时体模量和剪切模量的大幅但相等的分数硬化以及近乎温度不变的ν值都归因于单一机制：5f电子的局域化 - 离域化。