Elastic Constants of Yttrium Single Crystals in the Temperature Range 4.2–400°K

Abstract

The five independent elastic constants for yttrium single crystals have been determined by the pulse‐echo technique over the temperature range, 4.2–400°K. The experimental values extrapolated to 0°K are: C₁₁=8.34±0.02, C₃₃=8.01±0.02, C₄₄=2.690±0.006, C₁₂=2.91±0.03, and C₁₃=1.9±0.4 in units of 10¹¹ d/cm². The degree of elastic anisotropy is low throughout the entire temperature range. The curves illustrating the temperature dependence of the elastic constants show several inflections, and the curve for C₁₁ crosses that for C₃₃ near 390°K. The behavior is somewhat unusual, and is probably explicable on the basis that the degree of band overlap in yttrium is quite sensitive to interatomic spacing. Such a sensitivity has previously been postulated to explain the temperature dependence of the Hall coefficient.