skip to main content

SciTech ConnectSciTech Connect

Title: Strength and structural phase transitions of gadolinium at high pressure from radial X-ray diffraction

Lattice strength and structural phase transitions of gadolinium (Gd) were determined under nonhydrostatic compression up to 55 GPa using an angle-dispersive radial x-ray diffraction technique in a diamond-anvil cell at room temperature. Three new phases of fcc structure, dfcc structure, and new monoclinic structure were observed at 25 GPa, 34 GPa, and 53 GPa, respectively. The radial x-ray diffraction data yield a bulk modulus K{sub 0} = 36(1) GPa with its pressure derivate K{sub 0}′ = 3.8(1) at the azimuthal angle between the diamond cell loading axis and the diffraction plane normal and diffraction plane ψ = 54.7°. With K{sub 0}′ fixed at 4, the derived K{sub 0} is 34(1) GPa. In addition, analysis of diffraction data with lattice strain theory indicates that the ratio of differential stress to shear modulus (t/G) ranges from 0.011 to 0.014 at pressures of 12–55 GPa. Together with estimated high-pressure shear moduli, our results show that Gd can support a maximum differential stress of 0.41 GPa, while it starts to yield to plastic deformation at 16 GPa under uniaxial compression. The yield strength of Gd remains approximately a constant with increasing pressure, and reaches 0.46 GPa at 55 GPa.
Authors:
; ; ; ;  [1] ;  [2]
  1. Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)
  2. Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Texas 78712 (United States)
Publication Date:
OSTI Identifier:
22399152
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 24; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COMPRESSION; DIAMONDS; FCC LATTICES; GADOLINIUM; LOADING; MONOCLINIC LATTICES; PHASE TRANSFORMATIONS; PLASTICITY; PRESSURE DEPENDENCE; PRESSURE RANGE GIGA PA; SHEAR; STRAINS; STRESSES; TEMPERATURE RANGE 0273-0400 K; X-RAY DIFFRACTION; YIELD STRENGTH