Elastic Properties of Polycrystalline Solid Helium
نویسندگان
چکیده
Recent experiments have shown that the shear modulus of solid helium undergoes a large temperature variation in the range 20 to 200 mK, possibly due to changes in the pinning of dislocations. In this note we report on computer simulations of the elastic properties of polycrystalline solid helium. We calculate how the elastic coefficients of a sample made up of a large number of randomly oriented grains are affected by the changes in the shear modulus c44 of the individual grains.
منابع مشابه
Excitations of amorphous solid helium
We present neutron scattering measurements of the dynamic structure factor, S(Q, ω), of amorphous solid helium confined in 47 Å pore diameter MCM-41 at pressure 48.6 bar. At low temperature, T = 0.05 K, we observe S(Q, ω) of the confined quantum amorphous solid plus the bulk polycrystalline solid between the MCM-41 powder grains. No liquid-like phonon-roton modes, other sharply defined modes at...
متن کاملFacile measurement of single-crystal elastic constants from polycrystalline samples
Elastic constants are among the most fundamental properties of materials. Simulations of microstructural evolution and constitutive/micro-mechanistic modeling of materials properties require elastic constants that are predominately measured from single crystals that are labor intensive to grow. A facile technique is developed to measure elastic constants from polycrystalline samples. The techni...
متن کاملElastic Wave Propagation at Imperfect Boundary of Micropolar Elastic Solid and Fluid Saturated Porous Solid Half-Space
This paper deals with the reflection and transmission of elastic waves from imperfect interface separating a micropolar elastic solid half-space and a fluid saturated porous solid half-space. Longitudinal and transverse waves impinge obliquely at the interface. Amplitude ratios of various reflected and transmitted waves are obtained and computed numerically for a specific model and results obta...
متن کاملAb Initio Predicted Alloying Effects on the Elastic Properties of AlxHf1−xNbTaTiZr High Entropy Alloys
Using ab initio alloy theory, we investigate the equilibrium bulk properties and elastic mechanics of the single bcc solid-solution AlxHf1−xNbTaTiZr (x = 0–0.7, 1.0) high entropy alloys. Ab initio predicted equilibrium volume is consistent with the available experiment. We make a detailed investigation of the alloying effect of Al and Hf on the equilibrium volume, elastic constants and polycrys...
متن کاملAtomic helium scattering and diffraction from solid surfaces
It is shown that whether or not diffractive scattering is observed from solid surfaces depends not only on the elastic scattering cross section, ie the normalized Debye-Waller factor, as has been recently suggested by J L Beeby but also on the surface structure or local surface potential of the particular solid.
متن کامل