Evidence of FCC titanium hydride formation in. beta. titanium alloy: An X-ray diffraction study
Three types of titanium hydrides have been reported: delta, epsilon and ..gamma.. hydrides. The delta hydride forms in the composition range from TiH/sub 1.5/ to TiH/sub 1.99/ and has a CaF/sub 2/ structure with metal atoms on an fcc lattice and hydrogen atoms randomly occupying tetrahedral interstitial sites. At higher hydrogen concentrations, TiH/sub 2/, the fct (c/a < 1) epsilon hydride phase is formed below 310 K. The c/a ratio decreases with a decreasing temperature and it reaches and maintains a minimum value of 0.943 below 80 K. The fcc to tetragonal, delta ..-->.. epsilon transformation is apparently diffusionless, similar to that operating in the cubic/tetragonal transformation in zirconium hydride. The metastable fct ..gamma.. hydride having a c/a value of 1.09 or 1.12 forms from solid solutions of hydrogen in the hcp ..cap alpha.. matrix. While the titanium hydride precipitation in ..cap alpha..-Ti and its alloys has attracted extensive investigation, hydride formation in bcc ..beta..-Ti alloys has rarely been studied because they have not been thought to be liable to hydride formation. This paper shows conclusive evidence for the fcc delta hydride phase formation in the ..beta.. phase Ti-30 wt% Mo by x-ray diffraction study.
- Research Organization:
- Dept. of Materials Science and Materials Research Lab., Univ. of Illinois at Urbana-Champaign, 1304 W. Green Street, Urbana, IL 61801
- DOE Contract Number:
- AC02-76ER01198
- OSTI ID:
- 7007320
- Journal Information:
- Scr. Metall.; (United States), Journal Name: Scr. Metall.; (United States) Vol. 20:9; ISSN SCRMB
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360102* -- Metals & Alloys-- Structure & Phase Studies
360602 -- Other Materials-- Structure & Phase Studies
ALKALINE EARTH METAL COMPOUNDS
ALLOYS
CALCIUM COMPOUNDS
CALCIUM FLUORIDES
CALCIUM HALIDES
CHEMICAL REACTIONS
COHERENT SCATTERING
CRYSTAL DEFECTS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CUBIC LATTICES
DIFFRACTION
ELEMENTS
FCC LATTICES
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
HYDRIDATION
HYDRIDES
HYDROGEN
HYDROGEN COMPOUNDS
INTERSTITIALS
LOW TEMPERATURE
MOLYBDENUM ALLOYS
NONMETALS
PHASE TRANSFORMATIONS
POINT DEFECTS
QUANTITY RATIO
SCATTERING
TEMPERATURE EFFECTS
TITANIUM ALLOYS
TITANIUM BASE ALLOYS
TITANIUM COMPOUNDS
TITANIUM HYDRIDES
TRANSITION ELEMENT COMPOUNDS
X-RAY DIFFRACTION